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EP4136681A1 - Method for manufacturing a device for emitting radiation - Google Patents

Method for manufacturing a device for emitting radiation

Info

Publication number
EP4136681A1
EP4136681A1 EP21717112.3A EP21717112A EP4136681A1 EP 4136681 A1 EP4136681 A1 EP 4136681A1 EP 21717112 A EP21717112 A EP 21717112A EP 4136681 A1 EP4136681 A1 EP 4136681A1
Authority
EP
European Patent Office
Prior art keywords
face
substrate
emitting diode
emission
radiation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP21717112.3A
Other languages
German (de)
French (fr)
Inventor
Julien Pernot
Gwenole JACOPIN
Bruno Daudin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Centre National de la Recherche Scientifique CNRS
Universite Grenoble Alpes
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Original Assignee
Centre National de la Recherche Scientifique CNRS
Commissariat a lEnergie Atomique CEA
Universite Grenoble Alpes
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Centre National de la Recherche Scientifique CNRS, Commissariat a lEnergie Atomique CEA, Universite Grenoble Alpes, Commissariat a lEnergie Atomique et aux Energies Alternatives CEA filed Critical Centre National de la Recherche Scientifique CNRS
Publication of EP4136681A1 publication Critical patent/EP4136681A1/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/005—Processes
    • H01L33/0062—Processes for devices with an active region comprising only III-V compounds
    • H01L33/0075—Processes for devices with an active region comprising only III-V compounds comprising nitride compounds
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/0004—Devices characterised by their operation
    • H01L33/0008—Devices characterised by their operation having p-n or hi-lo junctions
    • H01L33/0012—Devices characterised by their operation having p-n or hi-lo junctions p-i-n devices
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/005—Processes
    • H01L33/0062—Processes for devices with an active region comprising only III-V compounds
    • H01L33/0066—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound
    • H01L33/007—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound comprising nitride compounds
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/005—Processes
    • H01L33/0093—Wafer bonding; Removal of the growth substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
    • H01L2933/0091—Scattering means in or on the semiconductor body or semiconductor body package
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/08—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/20—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular shape, e.g. curved or truncated substrate

Definitions

  • TITLE Manufacturing process of a radiation emitting device
  • the present invention relates to a method of manufacturing a transmitter device.
  • emitting devices have light emitting diodes configured to emit radiation when an electric current passes through them.
  • Such diodes include a p-doped portion, an n-doped portion and frequently an intermediate portion interposed between the n and p portions and intended to emit the radiation.
  • one of the n and p portions is integral with a substrate and the other p or n portion is frequently covered with a material transparent to the emitted radiation and electrically conductive, serving as an electrode and / or a layer. protection of the light-emitting diode against mechanical or chemical attack and allowing the extraction of radiation from the light-emitting diode.
  • the light-emitting diode is generally obtained by successive deposition on the substrate of the different layers of material forming the different portions of the diode, the layer of transparent and conductive material then being deposited on the light-emitting diode so as to form a continuous film covering at least partially the diode.
  • Such techniques make it possible in particular to obtain very thin films, requiring little material, and where appropriate to structure the film by photolithography methods for example, to obtain electrodes making it possible to address individual areas of the diode. .
  • ITO indium-tin oxide
  • the conductive materials and likely to be deposited in thin films on light emitting diodes are not optimized.
  • known materials such as I ⁇ TO are not or only slightly transparent to radiation. This results in degraded emission efficiency of the emitter, since part of the emitted radiation is absorbed by the ITO layer.
  • an emitting device comprising a light-emitting diode configured to emit radiation, the light-emitting diode comprising a first portion, a second portion and an emission portion, the first portion being produced in a first semiconductor material exhibiting a first type of doping, the second portion being made of a second semiconductor material exhibiting a second type of doping different from the first type of doping, the emission portion being interposed between the first portion and the second portion, the emission portion being made of a semiconductor emission material configured to emit the radiation when the light-emitting diode is traversed by an electric current, the method comprising the steps of:
  • a substrate made at least partially of a semiconductor substrate material exhibiting the first type of doping, the substrate material being transparent to radiation, the substrate having a first face delimiting the substrate in a direction normal to the first face,
  • the substrate further comprising a surface portion and an internal portion, the weakened portion separating the surface portion from the internal portion in the normal direction
  • the light-emitting diode by depositing at least the first material, the emission material and the second material, the first portion being interposed in the normal direction between the emission portion and the first face, the surface portion of the substrate being integral with the first portion, the light-emitting diode being delimited in the normal direction by the first face and by an end face of the second portion,
  • the method comprises one or more of the following characteristics, taken in isolation or in any technically possible combination: the set of atoms implanted in the substrate to form a weakened portion comprises hydrogen atoms.
  • the substrate material is diamond.
  • the substrate material is aluminum nitride.
  • - radiation is ultra-violet radiation, in particular radiation with an average wavelength of between 250 nanometers and 280 nanometers.
  • the first material, the second material and the third material are element III nitrides, and / or
  • the substrate material is monocrystalline.
  • the first type of doping is p-type doping.
  • the method further comprises a step of providing a power supply circuit for the light emitting diode and a step of connecting the surface portion to the power supply circuit.
  • the light-emitting diode comprises a set of nanowires each extending in the normal direction, each nanowire comprising a base made of the first material, an intermediate portion made of the emission material and an end portion made of the second material , the first portion being formed by the meeting of the bases of the nanowires, the emission portion being formed by the meeting of the intermediate portions, the second portion being formed by the meeting of the end portions.
  • the process includes one of the following steps:
  • the support comprises a metal portion delimited by the second face, the metal portion being fixed to the light emitting diode during the fixing step.
  • FIG. 1 is a schematic representation of an example of a transmitter device according to the invention
  • FIG. 2 is a flowchart of the steps of an exemplary method of manufacturing a transmitter device of FIG. 1,
  • FIG 3 is a schematic representation of the structure obtained during a step of the process of Figure 2,
  • FIG 4 is a schematic representation of the structure obtained during another step of the process of Figure 2, and
  • FIG 5 is a schematic representation of the structure obtained in yet another step of the process of Figure 2.
  • FIG. 1 An example of a transmitter device 10 is shown in FIG. 1.
  • the emitting device 10 is configured to emit radiation.
  • Each radiation includes a set of electromagnetic waves.
  • a wavelength is defined for each electromagnetic wave.
  • Each set corresponds to a range of wavelengths.
  • the wavelength range is the group formed by the set of wavelengths in the set of electromagnetic waves.
  • An average wavelength is defined for the wavelength range.
  • the radiation is, for example, ultraviolet radiation. Radiation with an average wavelength between 10 nanometers (nm) and 400 nm is an example of ultraviolet radiation.
  • the radiation has an average wavelength between 250 nm and 280 nm, for example equal to 265 nm.
  • the radiation is, for example, visible radiation.
  • Radiation with an average wavelength between 400 nm and 800 nm is an example of visible light.
  • the emitting device 10 comprises a support 15, a light emitting diode 20, a window layer 25 and a control circuit.
  • a stacking direction D is defined for the sending device 10.
  • the support 15, the light emitting diode 20 and the window layer 25 are superimposed in this order according to the stacking direction D.
  • Support 15 is configured to support light emitting diode 20.
  • the support 15 comprises, for example, a base 30 and a reflection layer 35.
  • the base 30 is made, for example, of a metallic material such as copper.
  • the base 30 is, for example, a plate extending in a plane perpendicular to the stacking direction D. However, it should be noted that the shape of the base 30 is liable to vary.
  • the reflection layer 35 is interposed between the base 30 and the light-emitting diode 20 in the stacking direction D.
  • Reflection layer 35 is configured to reflect radiation.
  • the reflection layer 35 is made of an electrically conductive material. According to one embodiment, the reflection layer 35 is electrically connected to the control circuit.
  • the reflection layer 35 is made, for example, of a metallic material.
  • the reflection layer 35 is made of aluminum.
  • the reflection layer 35 may be replaced by a metallic portion of the support 15 not forming a layer distinct from the base 30 but electrically conductive and / or configured to at least partially reflect the radiation.
  • the support 15 is a single layer.
  • Each light emitting diode 20 is configured to emit the radiation.
  • Each light emitting diode 20 is a semiconductor structure comprising several semiconductor areas forming a P-N or P-l-N junction and configured to emit light when an electric current flows through the different semiconductor areas.
  • each light emitting diode 20 has a first portion 40, an emission portion 45 and a second portion 50.
  • the first portion 40, the transmitting portion 45 and the second portion 50 are superimposed in this order according to the stacking direction D.
  • the transmitting portion 45 is interposed between the first portion 40 and the second portion 50 .
  • the light-emitting diode is, for example, formed by one or a set of three-dimensional structures.
  • a three-dimensional structure is a structure that extends along a main direction.
  • the three-dimensional structure has a length measured along the main direction.
  • the three-dimensional structure also has a maximum lateral dimension measured along a lateral direction perpendicular to the principal direction, the lateral direction being the direction perpendicular to the principal direction along which the dimension of the structure is greatest.
  • the maximum lateral dimension is, for example, less than or equal to 10 micrometers ( ⁇ m), and the length is greater than or equal to the maximum lateral dimension.
  • the maximum lateral dimension is advantageously less than or equal to 2.5 ⁇ m.
  • the maximum lateral dimension is, in particular, greater than or equal to 10 nm. In specific embodiments, the length is greater than or equal to twice the maximum lateral dimension, for example it is greater than or equal to five times the maximum lateral dimension.
  • the main direction is, for example, the stacking direction D.
  • the length of the three-dimensional structure is called "height" and the maximum dimension of the three-dimensional structure, in a plane perpendicular to the stacking direction D , is less than or equal to 10 ⁇ m.
  • the maximum dimension of the three-dimensional structure, in a plane perpendicular to the stacking direction D, is often referred to as the "diameter" regardless of the shape of the cross-section of the three-dimensional structure.
  • each three-dimensional structure is a microfilament.
  • a microfilament is a cylindrical three-dimensional structure.
  • the micro-thread is a cylinder extending along the stacking direction D.
  • the micro-thread is a cylinder with a circular base.
  • the diameter of the base of the cylinder is less than or equal to half the length of the microfilament.
  • a microfilament whose maximum lateral dimension is less than 1 ⁇ m is called a "nanowire”.
  • a pyramid extending along the stacking direction D from substrate 12 is another example of a three-dimensional structure.
  • Another example of a three-dimensional structure is a cone extending along the stacking direction D.
  • a truncated cone or a truncated pyramid extending along the stacking direction D is yet another example of a three-dimensional structure.
  • the light-emitting diode is a planar diode formed by the stack, in the stacking direction D, of at least one layer of semiconductor material forming the first portion 40, of at least one layer of semiconductor material forming the emission portion 45 and at least one layer of semiconductor material forming the second portion 50, each of these layers extending in a plane perpendicular to the direction of stacking D.
  • the first portion 40 is delimited along the stacking direction D by the transmission portion 45 and the window layer 25.
  • the first portion 40 is made of a first semiconductor material.
  • a semiconductor material is a material having a band gap value strictly greater than zero and less than or equal to 6.5 electron volts (eV).
  • eV electron volts
  • the valence band is defined as being, among the energy bands that are allowed for the electrons in the material, the band that has the highest energy while being completely filled at a temperature of 20 Kelvin or less ( K).
  • a first energy level is defined for each valence band.
  • the first energy level is the highest energy level in the valence band.
  • the conduction band is defined as being, among the energy bands which are allowed for the electrons in the material, the band which has the lowest energy while not being completely filled at a temperature less than or equal to 20 K.
  • a second energy level is defined for each conduction band.
  • the second energy level is the lowest energy level in the conduction band.
  • each band gap value is measured between the first energy level and the second energy level of the material.
  • a direct bandgap semiconductor is an example of a semiconductor material.
  • a material is considered to have a “direct bandgap” when the minimum of the conduction band and the maximum of the valence band correspond to the same value of momentum of charge carriers.
  • a material is considered to have an "indirect band gap" when the minimum of the conduction band and the maximum of the valence band correspond to different values of momentum of charge carriers.
  • Each semiconductor material can be chosen, for example, from the set formed by semiconductors III-V, in particular nitrides of elements III, semiconductors II-VI, or even semiconductors. IV-IV.
  • III-V semiconductors include in particular InAs, GaAs, AlAs and their alloys, InP, GaP, AIP and their alloys, and element III nitrides, which are AIN, GaN, InN and their alloys such as AIGaN or still InGaN.
  • the II-VI semiconductors include in particular CdTe, HgTe, CdSe, HgSe, and their alloys.
  • IV-IV semiconductors include in particular diamond, Si, Ge and their alloys.
  • the first semiconductor material is, for example, AIN or AIGaN, in particular when the radiation is ultraviolet radiation.
  • the first semiconductor material is, for example, GaN, or else a III-V semiconductor.
  • the first material exhibits a doping of a first type.
  • the first type of doping is chosen from p-type doping and n-type doping.
  • the first type of doping is p-type doping.
  • Doping is defined as the presence, in a material, of impurities providing free charge carriers.
  • Impurities are, for example, atoms of an element that is not naturally present in the material.
  • the doping is p-type.
  • a layer of gallium nitride, GaN, or gallium aluminum nitride, AIGaN is p-doped by adding magnesium (Mg) atoms.
  • the p-type doping is, for example, obtained by adding atoms of indium In and magnesium Mg.
  • the doping is n-type.
  • a layer of gallium nitride, GaN is n-doped by adding silicon (Si) atoms.
  • a thickness of the first portion 40, measured along the stacking direction D, is for example between 50 nm and 5 ⁇ m.
  • the first portion 40 comprises a p-doped electron blocking layer made of a semiconductor material having a forbidden band strictly greater than the forbidden band of the second material.
  • the electron blocking layer is, for example, made of AIGaN.
  • the electron blocking layer is, in particular, delimited along the stacking direction D by the emission portion 45.
  • the emitting portion 45 is configured to emit radiation when an electric current passes through the light emitting diode 20.
  • the emission portion 45 is made of an emission material.
  • the emission material is a semiconductor material.
  • the emission material has a band gap value that is strictly less than the band gap value of the first semiconductor material.
  • the emission semiconductor material is AIGaN.
  • the emission portion 45 comprises a quantum well or a set of quantum wells.
  • a quantum well is a structure in which quantum confinement occurs, in one direction, for at least one type of charge carriers.
  • the effects of quantum confinement occur when the dimension of the structure along this direction becomes comparable to or smaller than the De Broglie wavelength of carriers, which are usually electrons and / or holes, leading to levels of d 'energy called "energy sub-bands".
  • carriers can exhibit only discrete energy values but are generally able to move within a plane perpendicular to the direction in which confinement occurs.
  • the energy values available to carriers, also called “energy levels”, increase as the dimensions of the quantum well decrease along the direction in which confinement occurs.
  • the "De Broglie wavelength” is the wavelength of a particle when the particle is considered a wave.
  • the De Broglie wavelength of electrons is also called the “electron wavelength”.
  • the De Broglie wavelength of a charge carrier depends on the material of which the quantum well is made.
  • An emitter layer whose thickness is strictly less than the product of the electronic wavelength of the electrons in the semiconductor material that the emitter layer is made of and five is an example of a quantum well.
  • Another example of a quantum well is an emitting layer whose thickness is strictly less than the product of the De Broglie wavelength of excitons in the semiconductor material of which the emitting layer is made and five.
  • An exciton is a quasi-particle comprising an electron and a hole.
  • a quantum well often has a thickness of between 1 nm and 200 nm.
  • the quantum well (s) are for example constituted by a layer of emission material interposed between two layers of a material, for example of the first semiconductor material, having a band gap value strictly greater than that of the material. resignation.
  • the emission portion 45 comprises one or more layer (s) of the emission material, in particular of AIGaN, interposed between layers of AIN or of an AIGaN with a higher aluminum content than the emission material.
  • the emitting material is InGaN, and the InGaN layer (s) is (are) interposed between GaN layers.
  • the emission portion 45 is, for example, undoped. However, according to possible variants, the emission portion 45 is capable of exhibiting the first or the second type of doping.
  • the emission material making up the quantum well (s) is undoped, and the material making up the layers enclosing the emission material exhibits doping of the first or second type.
  • the second portion 50 is interposed between the emission portion 45 and the support 15, in particular between the emission portion 45 and the reflection layer 35.
  • the second portion 50 is made of a second semiconductor material.
  • the second semiconductor material has a band gap value that is strictly greater than the band gap value of the emission material.
  • the second semiconductor material is identical, except for the type of doping, to the first material.
  • the second semiconductor material is AIN.
  • the second material is AIGaN, or even GaN.
  • the second semiconductor material has a second type of doping different from the first type of doping.
  • the second type of doping is chosen from n-type doping and p-type doping.
  • the second type of doping is n-type doping.
  • the second portion 50 has a thickness, measured along the stacking direction D, for example between 50 nm and 1 ⁇ m.
  • the light-emitting diode 20 comprises a set of three-dimensional structures
  • the light-emitting diode 20 is, for example, formed by the joining of a set of elementary light-emitting diodes, each elementary light-emitting diode comprising a three-dimensional structure, a part of which forms part of the first portion 40, another part forms a part of the emission portion 45 and a part forms a part of the second portion 50.
  • each elementary light-emitting diode is a nanowire comprising a primary portion 55 (or “base”), an intermediate portion 60 and a secondary portion 65 (or “end portion”), superimposed in this order in the direction of. stacking D.
  • the primary portion 55 is delimited along the stacking direction D by the window layer 25 and by the intermediate portion 60.
  • the primary portion 55 is made of the first semiconductor material.
  • the first portion 40 is formed by all of the primary portions 55 of the various elementary light-emitting diodes.
  • Each primary portion 55 extends in the direction of stacking D.
  • Each primary portion 55 is, for example, cylindrical. It is understood by “cylindrical” that each primary portion 55 has a uniform section in any plane perpendicular to the stacking direction D. The section is, for example, circular, or even hexagonal.
  • the primary portions 55 are, for example, separated from each other. In particular, each primary portion 55 is remote from the other primary portions 55.
  • the intermediate portion 60 is delimited along the stacking direction D by the primary portion 55 and the secondary portion 65.
  • the intermediate portion 60 is made of the semiconductor emission material.
  • the emission portion 45 is formed by all of the intermediate portions 60 of the various elementary light-emitting diodes.
  • Each intermediate portion 60 is, for example, cylindrical.
  • the section of the intermediate portion 60 in a plane perpendicular to the stacking direction D is, for example, circular, or even hexagonal.
  • the intermediate portions 60 are, for example, separated from each other. In particular, each intermediate portion 60 is distant from the other intermediate portion 60.
  • the secondary portion 65 is delimited along the stacking direction D by the intermediate portion 60 and by the support 15, in particular by the reflection layer 35.
  • the secondary portion 65 is made of the second semiconductor material.
  • the second portion 50 is formed by all of the secondary portions 65 of the various elementary light-emitting diodes.
  • Each secondary portion 65 is, for example, cylindrical.
  • the section of the secondary portion 65 in a plane perpendicular to the stacking direction D is, for example, circular, or even hexagonal.
  • each secondary portion 65 is conical or pyramidal.
  • a dimension of the secondary portion 65 in a plane perpendicular to the stacking direction 65 increases as it moves away from the intermediate portion 60.
  • the secondary portions 65 of the various elementary light-emitting diodes are integral with one another, and present a continuity of material to each other.
  • the window layer 25 is designed to be traversed by the radiation. Further, window layer 25 is electrically conductive.
  • Window layer 25 is, in particular, monocrystalline.
  • the window layer is polycrystalline or nanocrystalline, that is to say formed of multiple crystals, each crystal having nanometric dimensions.
  • the window layer 25 is made of a semiconductor material, hereinafter referred to as the substrate material.
  • the substrate material is transparent to radiation.
  • the substrate material has a band gap value that is strictly greater than the band gap value of the emission material.
  • the substrate material has a band gap value that is strictly greater than the band gap value of the first material.
  • the substrate material is, for example, diamond.
  • the substrate material is I ⁇ IN.
  • the substrate material exhibits doping of the first type.
  • a resistivity of the substrate material is, for example, between 10 3 Ohm - centimeter (W.ah) and 10 4 Q.cm.
  • the window layer 25 has a thickness, measured along the stacking direction D, of between 10 nm and 1 ⁇ m.
  • Window layer 25 is, for example, electrically connected to the control circuit.
  • the control circuit is configured to generate an electric current passing through the light emitting diode 20.
  • the electric current successively passes through the reflection layer 35, the light emitting diode 20 and the window layer 25.
  • the electric current is capable of causing the emission of radiation by the light emitting diode 20 when the electric current passes through the light emitting diode 20.
  • the manufacturing process includes a supply step 100, an implantation step 110, a training step 120, a fixing step 130 and a breaking step 140.
  • a substrate 70 is provided.
  • the substrate 70 is in particular visible in FIG. 3.
  • the substrate 70 is made at least partially of the substrate material.
  • the substrate 70 comprises at least one portion 75 made of the substrate material.
  • the portion 75 is, for example, a layer of substrate material carried by a plate 80 (or “wafer”) serving as a support for the layer.
  • the layer 75 of substrate material is carried by a plate 80 made of the same material as the substrate material, the plate 80 being differentiated by the fact that the material making up the plate 80 is undoped or has less doping. as the substrate material.
  • the plate 80 is made of undoped or lightly doped diamond.
  • the substrate 70 is made entirely from the substrate material.
  • the portion 75 forms the entirety of the substrate 70.
  • Portion 75 is, for example, monocrystalline.
  • layer 75 and plate 80 are each single crystal.
  • the substrate 70 is monocrystalline.
  • the substrate has a first face 85.
  • the first face 85 is, for example, flat.
  • the first face 85 delimits the substrate 70, in particular the portion 75 of substrate material, in a direction N normal to the first face 85.
  • the layer 75 extends in a plane perpendicular to the normal direction N.
  • the first face 85 comprises a mask, that is to say a layer partially covering the first face 85.
  • the mask is made of a material preventing the deposition of the first material on the mask, of so that, as will appear subsequently, the deposition of the first material takes place only on the portions of the first face 85 without a mask.
  • the mask is, for example, made of titanium nitride TiN, or else of silicon nitride (Si x N y ), of T1O2, of S1O2 or of graphene.
  • a set of atoms are implanted in the substrate material.
  • Atoms are, for example, hydrogen atoms. However, other types of atoms are likely to be used.
  • the surface density of hydrogen atoms is, for example, between 10 15 and 10 18 cnr 2 .
  • the implantation depth is, for example, between 10 nm and 1 ⁇ m.
  • the atoms are, in particular, implanted in the substrate material through the first face 85.
  • the implantation step 110 there is obtained, in the substrate material, in particular in the portion 75, a weakened portion 90, a surface portion 92 and an internal portion 95.
  • the portion of substrate material 75 is formed by joining the embrittled portion 90, the surface portion 92 and the inner portion 95.
  • the embrittled portion 90 is the portion of the substrate material 75 in which the implanted atoms are present.
  • the weakened portion 90 extends parallel to the first face 85, therefore in a plane perpendicular to the normal direction N.
  • the implanted atoms are projected onto the first face 85, during the implantation step 110, with an identical speed for all the atoms, the depth at which each atom is implanted, measured according to the normal direction N from the first face 85, is the same for all atoms.
  • a weakened portion 90 extending parallel to the first face 85 is obtained.
  • the implantation depth of atoms is between 10 nm and 1 pm. In particular, the implantation depth is equal to the thickness of the window layer 25 that it is desired to obtain at the end of the manufacturing process.
  • the weakened portion 90 separates the surface portion 92 from the internal portion 95.
  • the surface portion 92 is interposed in the normal direction N between the weakened portion 90 and the internal portion 95.
  • the internal portion 95 is formed by all of the portions of substrate material which are located at a distance. depth, relative to the first face 85, strictly greater than the implantation depth of the atoms.
  • the light emitting diode 20 is formed on the first face 85.
  • the first material, the emitting material and the second material are deposited in this order on the first face 85 so as to get the light emitting diode 20.
  • the light-emitting diode 20 is, for example, formed by chemical vapor deposition (in English “Chemical vapor deposition”, or CVD), or by molecular beam epitaxy (in English “Molecular Beam Epitaxy”).
  • the stacking direction D of the light emitting diode 20 coincides with the normal direction N.
  • the light emitting diode 20 is bounded by the first face 85 and by an end face 150 of the light emitting diode.
  • the first portion 40 is interposed between the first face 85 and the emission portion 45 in the normal direction N.
  • the first portion 40 is, in particular, delimited in the normal direction N by the first face 85 and by the emission portion 45.
  • the first portion 40 is integral with the surface portion 92.
  • the first portion grows epitaxially on the first face 85.
  • the three-dimensional structures making up the light-emitting diode are obtained by depositing the first material on the portions of the first face 85 without a mask, the first material not being deposited on the mask.
  • primary portions 55 separated from each other and extending in the normal direction N are obtained.
  • the deposition conditions, in particular temperature, during the formation step 120 are chosen so that the growth of the first material takes place naturally in the form of columns separated from each other.
  • the emission portion 45 and the second portion 50 are deposited on the columns forming the first portion 40, and naturally tend to maintain three-dimensional growth.
  • the forming step 120 comprises a step of coalescing the secondary portions 65 forming the second portion 50.
  • the conditions, in particular the temperature of the substrate 70, during the deposition of the second material are chosen so that the lateral dimension of the secondary portions 65 increase away from the intermediate portions 60 until the secondary portions 65 come into contact with each other and then merge to form a second integral portion 50.
  • the training step 120 includes a planarization step.
  • the planarization step involves the injection of a filling material into the space between the nanostructures, in particular the nanowires, forming the light emitting diode.
  • the filling material is transparent to radiation.
  • the filling material is electrically insulating.
  • the filling material is, for example, alumina Al 2 O 3 .
  • the end face 150 of the light-emitting diode 20 is planarized, for example by mechanical or mechanical-chemical polishing.
  • the end face 150 is liable to exhibit, after the deposition of the second material, excessive roughness, in particular when the light-emitting diode 20 comprises a set of three-dimensional structures, since the height of these structures is liable to increase. vary from one structure to another because of variations in the diameter of these structures or even local variations in the density of structures.
  • the end face 150 of the light-emitting diode 20 is fixed to a face, called the second face 155, of the support 15, as shown in FIG. 4.
  • the second face 155 is. a face delimiting the reflection layer 35 along the stacking direction D.
  • the faces 150 and 155 are, for example, fixed to one another by depositing a metal layer, for example a layer of aluminum (for example by evaporation or by “Electron beam physical vapor deposition”) on the face 150, then by welding the support 15 to the aluminum layer, for example using a brazing metal interposed between the support 15 and the face 150.
  • a metal layer for example a layer of aluminum (for example by evaporation or by “Electron beam physical vapor deposition”) on the face 150, then by welding the support 15 to the aluminum layer, for example using a brazing metal interposed between the support 15 and the face 150.
  • the weakened portion 90 is broken so as to separate the surface portion 92 from the internal portion 95.
  • the surface portion 92 separated from the rest of the substrate 70 and integral with the first portion 40 of the light-emitting diode, forms the window layer 25.
  • the rupture of the weakened portion 90 is visible in particular in FIG. 5.
  • the weakened portion 90 is, for example, broken by heating the substrate 70 to a temperature and for a period of time suitable for causing in the weakened portion 90 the formation of bubbles of a gas formed by the implanted atoms.
  • the bubbles formed thus cause the embrittled portion 90 to rupture and the portion 75 of substrate material to separate along the embrittled portion 90.
  • control circuit is electrically connected to the surface portion 92, forming the window layer 25, and / or to the reflection layer 25.
  • this window layer 25 transparent to radiation is easily obtained.
  • this window layer is capable of being made of a material which is not suitable for deposition on the light-emitting diode 20, for example of a material which is deposited at temperatures liable to damage the light-emitting diode 20.
  • substrate materials such as diamond, both conductive and transparent to radiation.
  • the same substrate 70 is capable of being used a large number of times, a small thickness of substrate material (forming the surface portion 92) being removed each time.
  • the same substrate 70 can be used for the growth of numerous diodes 20 and for the manufacture of numerous emitter devices 10, which is particularly advantageous in the case of substrates 70 which are difficult to obtain, for example in the case of substrates 70 made of AIN or of AIN on silicon.
  • the rupture of the weakened portion 90 generates a surface roughness of the face of the window layer 25 which is opposite the light emitting diode 20, i.e. the face through which the radiation is intended to exit. of the window layer 25. This roughness facilitates the extraction of the radiation from the window layer 25 and therefore increases the efficiency of the device 10.
  • a characteristic length of the roughness is, for example, between 0.1 and 30 times a ratio between, in the numerator, the mean wavelength of the radiation and, in the numerator, the optical index at this wavelength of the material making up the window layer 25, this range of characteristic lengths allowing good extraction of the radiation.
  • the window layer 25 is likely to be monocrystalline if the substrate 70 used has a monocrystalline portion 75.
  • the transparency and / or the electrical conductivity of the window layer 25 are therefore improved compared to polycrystalline window layers 25.
  • Diamond is in particular a material transparent over a wide range of wavelengths and capable of being conductive, especially when it is heavily p-doped. Diamond is particularly suitable for the growth of element III nitrides, and transparent to radiation, especially UV, obtained by diodes made of these materials.
  • the three-dimensional structures and in particular the nanowires of element III nitrides and in particular AIN allow more efficient p-doping than two-dimensional structures.
  • the coalescence and / or the injection of filling material, followed (s) by polishing, make it possible to obtain faces 150 that are flat and allow good attachment to the reflection layer 35.
  • the injection of material filling prevents excessive damage to three-dimensional structures during polishing.
  • the emitting device 10 further comprises a converter (sometimes called a “phosphor”) configured to absorb all or part of the radiation and to emit in response a radiation having a length of. different mean wave, in particular strictly longer, than the mean wavelength of the emitted radiation.
  • the converter is then, for example, placed in contact with the window layer 25, the window layer 25 being in particular interposed between the converter and the light-emitting diode 20.
  • the substrate material is diamond and the first type of doping is p-doping is described in detail above, other configurations are conceivable, in particular configurations in which the first type of doping is. n doping and the second type of doping is p doping.
  • the first type of doping is n doping
  • the substrate material is AIN
  • n doped the second material is, for example, AIGaN p doped.
  • Such configurations include, for example, planar light emitting diodes 20, although configurations in which light emitting diodes 20 have three dimensional structures are also conceivable.
  • the electron blocking layer is then for example part of the second portion 50.
  • the substrate is p-doped diamond or p-doped GAIN
  • the first portion 40 is made of an element III nitride exhibiting p-type doping
  • the second portion 50 is made of a material exhibiting n-type doping
  • the emission portion 45 being interposed between the portions 40 and 50 and exhibiting n-type or p-type doping, or else being unintentionally doped.
  • the first portion 40 is, for example, made of an element III nitride exhibiting n-type doping
  • the second portion 50 is made of a material exhibiting p-type doping
  • the emission portion 45 being interposed between portions 40 and 50 and exhibiting n or p type doping, or else being unintentionally doped.

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Abstract

The invention relates to a method for manufacturing an emitter device (10), comprising the steps of: - providing a substrate (70) made of a semiconductor material having a first face (85) defining the substrate (70) in a direction (N) normal to the first face (85), - implanting, through the first face (85), atoms capable of forming a weakened portion in the substrate, the substrate (70) further comprising a surface portion (92) and an internal portion (95), the weakened portion (90) separating the surface portion (92) from the internal portion (95) in the normal direction (N), - forming, on the first face (85), a light-emitting diode (20), - fastening a face (150) of the diode (20) to a second face (155) of a support (15), and - breaking the weakened portion (90) in order to separate the surface portion (92) from the internal portion (95).

Description

TITRE : Procédé de fabrication d’un dispositif émetteur de rayonnement TITLE: Manufacturing process of a radiation emitting device
La présente invention concerne un procédé de fabrication d’un dispositif émetteur.The present invention relates to a method of manufacturing a transmitter device.
De nombreux dispositifs émetteurs comportent des diodes électroluminescentes configurées pour émettre un rayonnement lorsqu’elles sont traversées par un courant électrique. De telles diodes comportent une portion dopée p, une portion dopée n et fréquemment une portion intermédiaire interposée entre les portions n et p et destinée à émettre le rayonnement. De manière générale, l’une des portions n et p est solidaire d’un substrat et l’autre portion p ou n est fréquemment recouverte d’un matériau transparent au rayonnement émis et électriquement conducteur, servant d’électrode et/ou de couche de protection de la diode électroluminescente contre les agressions mécaniques ou chimiques et permettant l’extraction du rayonnement hors de la diode électroluminescente. Many emitting devices have light emitting diodes configured to emit radiation when an electric current passes through them. Such diodes include a p-doped portion, an n-doped portion and frequently an intermediate portion interposed between the n and p portions and intended to emit the radiation. In general, one of the n and p portions is integral with a substrate and the other p or n portion is frequently covered with a material transparent to the emitted radiation and electrically conductive, serving as an electrode and / or a layer. protection of the light-emitting diode against mechanical or chemical attack and allowing the extraction of radiation from the light-emitting diode.
La diode électroluminescente est en général obtenue par dépôt successif sur le substrat des différentes couches de matériau formant les différentes portions de la diode, la couche de matériau transparent et conducteur étant ensuite déposée sur la diode électroluminescente de manière à former un film continu couvrant au moins partiellement la diode. De telles techniques permettent notamment d’obtenir des films de très faible épaisseur, nécessitant peu de matériau, et le cas échéant de structurer le film par des méthodes de photolithographie par exemple, pour obtenir des électrodes permettant d’adresser des zones individuelles de la diode. The light-emitting diode is generally obtained by successive deposition on the substrate of the different layers of material forming the different portions of the diode, the layer of transparent and conductive material then being deposited on the light-emitting diode so as to form a continuous film covering at least partially the diode. Such techniques make it possible in particular to obtain very thin films, requiring little material, and where appropriate to structure the film by photolithography methods for example, to obtain electrodes making it possible to address individual areas of the diode. .
Un exemple très utilisé de matériau conducteur et transparent est l’oxyde d’indium- étain (en Anglais « Indium-Tin Oxide », ou ITO) A widely used example of a conductive and transparent material is indium-tin oxide (in English "Indium-Tin Oxide", or ITO)
Toutefois, il est à noter que les matériaux conducteurs et susceptibles d’être déposés en films minces sur des diodes électroluminescentes ne sont pas optimisés. En particulier, dans certaines gammes de longueurs d’onde telles que l’ultra-violet, les matériaux connus tels que IΊTO ne sont pas ou peu transparents au rayonnement. Il en résulte un rendement d’émission dégradé de l’émetteur, puisqu’une partie du rayonnement émis est absorbée par la couche d’ITO. However, it should be noted that the conductive materials and likely to be deposited in thin films on light emitting diodes are not optimized. In particular, in certain wavelength ranges such as ultra-violet, known materials such as IΊTO are not or only slightly transparent to radiation. This results in degraded emission efficiency of the emitter, since part of the emitted radiation is absorbed by the ITO layer.
Dans d’autres cas, une absorption non négligeable du rayonnement peut avoir lieu au niveau des joints de grains entre les différents grains composant le film, ces joints de grains diminuant également la conductivité électrique et thermique du matériau. Or, le dépôt des matériaux connus sur une diode électroluminescente tend à déboucher sur une couche non monocristalline et présentant donc de nombreux joints de grains, diminuant donc le rendement du dispositif. Il existe donc un besoin pour un procédé de fabrication d’un dispositif émetteur comportant une diode électroluminescente, qui présente un meilleur rendement que les dispositifs émetteurs de l’état de la technique. In other cases, a not insignificant absorption of the radiation can take place at the level of the grain boundaries between the different grains making up the film, these grain boundaries also reducing the electrical and thermal conductivity of the material. However, the deposition of known materials on a light-emitting diode tends to result in a non-monocrystalline layer and therefore having many grain boundaries, therefore reducing the efficiency of the device. There is therefore a need for a method of manufacturing an emitting device comprising a light-emitting diode, which has a better efficiency than the emitting devices of the state of the art.
A cet effet, il est proposé un procédé de fabrication d’un dispositif émetteur comportant une diode électroluminescente configurée pour émettre un rayonnement, la diode électroluminescente comportant une première portion, une deuxième portion et une portion d’émission, la première portion étant réalisée en un premier matériau semi- conducteur présentant un premier type de dopage, la deuxième portion étant réalisée en un deuxième matériau semi-conducteur présentant un deuxième type de dopage différent du premier type de dopage, la portion d’émission étant interposée entre la première portion et la deuxième portion, la portion d’émission étant réalisée en un matériau d’émission semi- conducteur configuré pour émettre le rayonnement lorsque la diode électroluminescente est traversée par un courant électrique, le procédé comportant des étapes de : To this end, there is proposed a method of manufacturing an emitting device comprising a light-emitting diode configured to emit radiation, the light-emitting diode comprising a first portion, a second portion and an emission portion, the first portion being produced in a first semiconductor material exhibiting a first type of doping, the second portion being made of a second semiconductor material exhibiting a second type of doping different from the first type of doping, the emission portion being interposed between the first portion and the second portion, the emission portion being made of a semiconductor emission material configured to emit the radiation when the light-emitting diode is traversed by an electric current, the method comprising the steps of:
- fourniture d’un substrat réalisé au moins partiellement en un matériau de substrat semi-conducteur présentant le premier type de dopage, le matériau de substrat étant transparent au rayonnement, le substrat présentant une première face délimitant le substrat selon une direction normale à la première face, supply of a substrate made at least partially of a semiconductor substrate material exhibiting the first type of doping, the substrate material being transparent to radiation, the substrate having a first face delimiting the substrate in a direction normal to the first face,
- implantation, à travers la première face, d’un ensemble d’atomes apte à former une portion fragilisée dans le matériau de substrat, la portion fragilisée s’étendant parallèlement à la première face, le substrat comportant en outre une portion de surface et une portion interne, la portion fragilisée séparant la portion de surface de la portion interne selon la direction normale, - implantation, through the first face, of a set of atoms capable of forming a weakened portion in the substrate material, the weakened portion extending parallel to the first face, the substrate further comprising a surface portion and an internal portion, the weakened portion separating the surface portion from the internal portion in the normal direction,
- formation, sur la première face, de la diode électroluminescente par dépôt au moins du premier matériau, du matériau d’émission et du deuxième matériau, la première portion étant interposée selon la direction normale entre la portion d’émission et la première face, la portion de surface du substrat étant solidaire de la première portion, la diode électroluminescente étant délimitée selon la direction normale par la première face et par une face d’extrémité de la deuxième portion, - Formation, on the first face, of the light-emitting diode by depositing at least the first material, the emission material and the second material, the first portion being interposed in the normal direction between the emission portion and the first face, the surface portion of the substrate being integral with the first portion, the light-emitting diode being delimited in the normal direction by the first face and by an end face of the second portion,
- fixation de la face d’extrémité à une deuxième face d’un support, la deuxième portion étant interposée selon la direction normale entre le support et la portion d’émission, et - fixing the end face to a second face of a support, the second portion being interposed in the normal direction between the support and the emission portion, and
- rupture de la portion fragilisée pour séparer la portion de surface du matériau de substrat de la portion interne du matériau de substrat. breaking the weakened portion to separate the surface portion of the substrate material from the internal portion of the substrate material.
Selon des modes de réalisation particuliers de l’invention, le procédé comporte une ou plusieurs des caractéristiques suivantes, prise(s) isolément ou selon toutes les combinaisons techniquement possibles : - l’ensemble d’atomes implanté dans le substrat pour former une portion fragilisée comprend des atomes d’hydrogène. According to particular embodiments of the invention, the method comprises one or more of the following characteristics, taken in isolation or in any technically possible combination: the set of atoms implanted in the substrate to form a weakened portion comprises hydrogen atoms.
- le matériau de substrat est le diamant. - the substrate material is diamond.
- le matériau de substrat est le nitrure d’aluminium. - the substrate material is aluminum nitride.
- le rayonnement est un rayonnement ultra-violet, notamment un rayonnement présentant une longueur d’onde moyenne comprise entre 250 nanomètres et 280 nanomètres. - radiation is ultra-violet radiation, in particular radiation with an average wavelength of between 250 nanometers and 280 nanometers.
- au moins une des propriétés suivantes est vérifiée : - at least one of the following properties is verified:
- le premier matériau, le deuxième matériau et le troisième matériau sont des nitrures d’élément III, et/ou - the first material, the second material and the third material are element III nitrides, and / or
- le matériau de substrat est monocristallin. - the substrate material is monocrystalline.
- le premier type de dopage est le dopage de type p. - the first type of doping is p-type doping.
- le procédé comporte, en outre, une étape de fourniture d’un circuit d’alimentation de la diode électroluminescente et une étape de connexion de la portion de surface au circuit d’alimentation. - The method further comprises a step of providing a power supply circuit for the light emitting diode and a step of connecting the surface portion to the power supply circuit.
- la diode électroluminescente comporte un ensemble de nanofils s’étendant chacun selon la direction normale, chaque nanofil comportant une base réalisée en le premier matériau, une portion intermédiaire réalisée en le matériau d’émission et une portion d’extrémité réalisée en le deuxième matériau, la première portion étant formée par la réunion des bases des nanofils, la portion d’émission étant formée par la réunion des portions intermédiaires, la deuxième portion étant formée par la réunion des portions d’extrémité. the light-emitting diode comprises a set of nanowires each extending in the normal direction, each nanowire comprising a base made of the first material, an intermediate portion made of the emission material and an end portion made of the second material , the first portion being formed by the meeting of the bases of the nanowires, the emission portion being formed by the meeting of the intermediate portions, the second portion being formed by the meeting of the end portions.
- le procédé comporte l’une des étapes suivantes : - the process includes one of the following steps:
- une étape de coalescence des portions d’extrémité des nanofils pour former la face d’extrémité, et/ou - a step of coalescing the end portions of the nanowires to form the end face, and / or
- une étape d’injection d’un matériau de remplissage transparent au rayonnement entre les nanofils antérieurement à l’étape de fixation. - a step of injecting a filler material transparent to radiation between the nanowires prior to the fixing step.
- le support comporte une portion métallique délimitée par la deuxième face, la portion métallique étant fixée à la diode électroluminescente au cours de l’étape de fixation. - The support comprises a metal portion delimited by the second face, the metal portion being fixed to the light emitting diode during the fixing step.
Il est également proposé un dispositif émetteur susceptible d’être obtenu par un procédé selon l’une quelconque des revendications précédentes. There is also provided a transmitter device obtainable by a method according to any one of the preceding claims.
Des caractéristiques et avantages de l’invention apparaîtront à la lecture de la description qui va suivre, donnée uniquement à titre d’exemple non limitatif, et faite en référence aux dessins annexés, sur lesquels : Characteristics and advantages of the invention will become apparent on reading the description which follows, given solely by way of non-limiting example, and made with reference to the accompanying drawings, in which:
[Fig 1] la figure 1 est une représentation schématique d’un exemple de dispositif émetteur selon l’invention, [Fig 2] la figure 2 est un ordinogramme des étapes d’un exemple de procédé de fabrication d’un dispositif émetteur de la figure 1, [Fig 1] FIG. 1 is a schematic representation of an example of a transmitter device according to the invention, [Fig 2] FIG. 2 is a flowchart of the steps of an exemplary method of manufacturing a transmitter device of FIG. 1,
[Fig 3] la figure 3 est une représentation schématique de la structure obtenue lors d’une étape du procédé de la figure 2, [Fig 3] Figure 3 is a schematic representation of the structure obtained during a step of the process of Figure 2,
[Fig 4] la figure 4 est une représentation schématique de la structure obtenue lors d’une autre étape du procédé de la figure 2, et [Fig 4] Figure 4 is a schematic representation of the structure obtained during another step of the process of Figure 2, and
[Fig 5] la figure 5 est une représentation schématique de la structure obtenue lors d’une encore autre étape du procédé de la figure 2. [Fig 5] Figure 5 is a schematic representation of the structure obtained in yet another step of the process of Figure 2.
Un exemple de dispositif émetteur 10 est représenté sur la figure 1. An example of a transmitter device 10 is shown in FIG. 1.
Le dispositif émetteur 10 est configuré pour émettre un rayonnement. The emitting device 10 is configured to emit radiation.
Chaque rayonnement comprend un ensemble d’ondes électromagnétiques. Each radiation includes a set of electromagnetic waves.
Une longueur d’onde est définie pour chaque onde électromagnétique. A wavelength is defined for each electromagnetic wave.
Chaque ensemble correspond à une plage de longueurs d’onde. La plage de longueurs d’onde est le groupe formé par l’ensemble des longueurs d’onde de l’ensemble d’ondes électromagnétiques. Each set corresponds to a range of wavelengths. The wavelength range is the group formed by the set of wavelengths in the set of electromagnetic waves.
Une longueur d’onde moyenne est définie pour la plage de longueurs d’onde. An average wavelength is defined for the wavelength range.
Le rayonnement est, par exemple, un rayonnement ultraviolet. Un rayonnement présentant une longueur d’onde moyenne comprise entre 10 nanomètres (nm) et 400 nm est un exemple de rayonnement ultraviolet. The radiation is, for example, ultraviolet radiation. Radiation with an average wavelength between 10 nanometers (nm) and 400 nm is an example of ultraviolet radiation.
Par exemple, le rayonnement présente une longueur d’onde moyenne comprise entre 250 nm et 280 nm, par exemple égale à 265 nm. For example, the radiation has an average wavelength between 250 nm and 280 nm, for example equal to 265 nm.
En variante, le rayonnement est, par exemple, un rayonnement visible. Un rayonnement dont la longueur d’onde moyenne est comprise entre 400 nm et 800 nm est un exemple de lumière visible. Alternatively, the radiation is, for example, visible radiation. Radiation with an average wavelength between 400 nm and 800 nm is an example of visible light.
Le dispositif émetteur 10 comporte un support 15, une diode électroluminescente 20, une couche fenêtre 25 et un circuit de commande. The emitting device 10 comprises a support 15, a light emitting diode 20, a window layer 25 and a control circuit.
Il est défini une direction d’empilement D pour le dispositif émetteur 10. A stacking direction D is defined for the sending device 10.
Le support 15, la diode électroluminescente 20 et la couche fenêtre 25 sont superposés dans cet ordre selon la direction d’empilement D. The support 15, the light emitting diode 20 and the window layer 25 are superimposed in this order according to the stacking direction D.
Le support 15 est configuré pour supporter la diode électroluminescente 20. Support 15 is configured to support light emitting diode 20.
Le support 15 comporte, par exemple, une base 30 et une couche de réflexion 35.The support 15 comprises, for example, a base 30 and a reflection layer 35.
La base 30 est réalisée, par exemple, en un matériau métallique tel que le cuivre.The base 30 is made, for example, of a metallic material such as copper.
La base 30 est, par exemple, une plaque s’étendant dans un plan perpendiculaire à la direction d’empilement D. Toutefois, il est à noter que la forme de la base 30 est susceptible de varier. La couche de réflexion 35 est interposée entre la base 30 et la diode électroluminescente 20 selon la direction d’empilement D. The base 30 is, for example, a plate extending in a plane perpendicular to the stacking direction D. However, it should be noted that the shape of the base 30 is liable to vary. The reflection layer 35 is interposed between the base 30 and the light-emitting diode 20 in the stacking direction D.
La couche de réflexion 35 est configurée pour réfléchir le rayonnement. Reflection layer 35 is configured to reflect radiation.
Optionnellement, la couche de réflexion 35 est réalisée en un matériau électriquement conducteur. Selon un mode de réalisation, la couche de réflexion 35 est électriquement connectée au circuit de commande. Optionally, the reflection layer 35 is made of an electrically conductive material. According to one embodiment, the reflection layer 35 is electrically connected to the control circuit.
La couche de réflexion 35 est réalisée, par exemple, en un matériau métallique. En particulier, lorsque le rayonnement est un rayonnement ultraviolet, la couche de réflexion 35 est réalisée en aluminium. The reflection layer 35 is made, for example, of a metallic material. In particular, when the radiation is ultraviolet radiation, the reflection layer 35 is made of aluminum.
Il est à noter que dans certains cas la couche de réflexion 35 est susceptible d’être remplacée par une portion métallique du support 15 ne formant pas une couche distincte de la base 30 mais électriquement conductrice et/ou configurée pour réfléchir au moins en partie le rayonnement. Dans ce cas, le support 15 est mono couche. It should be noted that in certain cases the reflection layer 35 may be replaced by a metallic portion of the support 15 not forming a layer distinct from the base 30 but electrically conductive and / or configured to at least partially reflect the radiation. In this case, the support 15 is a single layer.
Chaque diode électroluminescente 20 est configurée pour émettre le rayonnement.Each light emitting diode 20 is configured to emit the radiation.
Chaque diode électroluminescente 20 est une structure semi-conductrice comprenant plusieurs zones semi-conductrices formant une jonction P-N ou P-l-N et configurée pour émettre de la lumière lorsqu’un courant électrique circule à travers les différentes zones semi-conductrices. Each light emitting diode 20 is a semiconductor structure comprising several semiconductor areas forming a P-N or P-l-N junction and configured to emit light when an electric current flows through the different semiconductor areas.
En particulier, chaque diode électroluminescente 20 comporte une première portion 40, une portion d’émission 45 et une deuxième portion 50. In particular, each light emitting diode 20 has a first portion 40, an emission portion 45 and a second portion 50.
La première portion 40, la portion d’émission 45 et la deuxième portion 50 sont superposées dans cet ordre selon la direction d’empilement D. En particulier, la portion d’émission 45 est interposée entre la première portion 40 et la deuxième portion 50. The first portion 40, the transmitting portion 45 and the second portion 50 are superimposed in this order according to the stacking direction D. In particular, the transmitting portion 45 is interposed between the first portion 40 and the second portion 50 .
La diode électroluminescente est, par exemple, formée par une ou un ensemble de structures tridimensionnelles. The light-emitting diode is, for example, formed by one or a set of three-dimensional structures.
Une structure tridimensionnelle est une structure qui s’étend le long d’une direction principale. La structure tridimensionnelle présente une longueur mesurée le long de la direction principale. La structure tridimensionnelle présente également une dimension latérale maximale mesurée le long d’une direction latérale perpendiculaire à la direction principale, la direction latérale étant la direction perpendiculaire à la direction principale le long de laquelle la dimension de la structure est la plus grande. A three-dimensional structure is a structure that extends along a main direction. The three-dimensional structure has a length measured along the main direction. The three-dimensional structure also has a maximum lateral dimension measured along a lateral direction perpendicular to the principal direction, the lateral direction being the direction perpendicular to the principal direction along which the dimension of the structure is greatest.
La dimension latérale maximale est, par exemple, inférieure ou égale à 10 micromètres (pm), et la longueur est supérieure ou égale à la dimension latérale maximale. La dimension latérale maximale est avantageusement inférieure ou égale à 2,5 pm. The maximum lateral dimension is, for example, less than or equal to 10 micrometers (µm), and the length is greater than or equal to the maximum lateral dimension. The maximum lateral dimension is advantageously less than or equal to 2.5 μm.
La dimension latérale maximale est, notamment, supérieure ou égale à 10 nm. Dans des modes de réalisation spécifiques, la longueur est supérieure ou égale à deux fois la dimension latérale maximale, par exemple elle est supérieure ou égale à cinq fois la dimension latérale maximale. The maximum lateral dimension is, in particular, greater than or equal to 10 nm. In specific embodiments, the length is greater than or equal to twice the maximum lateral dimension, for example it is greater than or equal to five times the maximum lateral dimension.
La direction principale est, par exemple, la direction d’empilement D. Dans ce cas, la longueur de la structure tridimensionnelle est appelée « hauteur » et la dimension maximale de la structure tridimensionnelle, dans un plan perpendiculaire à la direction d’empilement D, est inférieure ou égale à 10 pm. The main direction is, for example, the stacking direction D. In this case, the length of the three-dimensional structure is called "height" and the maximum dimension of the three-dimensional structure, in a plane perpendicular to the stacking direction D , is less than or equal to 10 μm.
La dimension maximale de la structure tridimensionnelle, dans un plan perpendiculaire à la direction d’empilement D, est souvent appelée « diamètre » quelle que soit la forme de la section transversale de la structure tridimensionnelle. The maximum dimension of the three-dimensional structure, in a plane perpendicular to the stacking direction D, is often referred to as the "diameter" regardless of the shape of the cross-section of the three-dimensional structure.
Par exemple, chaque structure tridimensionnelle est un microfil. Un microfil est une structure tridimensionnelle cylindrique. For example, each three-dimensional structure is a microfilament. A microfilament is a cylindrical three-dimensional structure.
Dans un mode de réalisation spécifique, le microfil est un cylindre s’étendant le long de la direction d’empilement D. Par exemple, le microfil est un cylindre à base circulaire. Dans ce cas, le diamètre de la base du cylindre est inférieur ou égal à la moitié de la longueur du microfil. In a specific embodiment, the micro-thread is a cylinder extending along the stacking direction D. For example, the micro-thread is a cylinder with a circular base. In this case, the diameter of the base of the cylinder is less than or equal to half the length of the microfilament.
Un microfil dont la dimension latérale maximale est inférieure à 1 pm est appelé un « nanofil ». A microfilament whose maximum lateral dimension is less than 1 µm is called a "nanowire".
Une pyramide s’étendant le long de la direction d’empilement D à partir du substrat 12 constitue un autre exemple de structure tridimensionnelle. A pyramid extending along the stacking direction D from substrate 12 is another example of a three-dimensional structure.
Un cône s’étendant le long de la direction d’empilement D constitue un autre exemple de structure tridimensionnelle. Another example of a three-dimensional structure is a cone extending along the stacking direction D.
Un cône tronqué ou une pyramide tronquée s’étendant le long de la direction d’empilement D constitue encore un autre exemple de structure tridimensionnelle. A truncated cone or a truncated pyramid extending along the stacking direction D is yet another example of a three-dimensional structure.
Il est à noter que selon une variante envisageable, la diode électroluminescente est une diode planaire formée par l’empilement, selon la direction d’empilement D, d’au moins une couche de matériau semi-conducteur formant la première portion 40, d’au moins une couche de matériau semi-conducteur formant la portion d’émission 45 et d’au moins une ouche de matériau semi-conducteur formant la deuxième portion 50, chacune de ces couches s’étendant dans un plan perpendiculaire à la direction d’empilement D. It should be noted that according to a possible variant, the light-emitting diode is a planar diode formed by the stack, in the stacking direction D, of at least one layer of semiconductor material forming the first portion 40, of at least one layer of semiconductor material forming the emission portion 45 and at least one layer of semiconductor material forming the second portion 50, each of these layers extending in a plane perpendicular to the direction of stacking D.
La première portion 40 est délimitée selon la direction d’empilement D par la portion d’émission 45 et la par couche fenêtre 25. The first portion 40 is delimited along the stacking direction D by the transmission portion 45 and the window layer 25.
La première portion 40 est réalisée en un premier matériau semi-conducteur. The first portion 40 is made of a first semiconductor material.
Un matériau semi-conducteur est un matériau présentant une valeur de bande interdite strictement supérieure à zéro et inférieure ou égale à 6,5 électrons-volts (eV). L’expression « valeur de bande interdite » doit être comprise comme étant la valeur de la bande interdite entre la bande de valence et la bande de conduction du matériau. A semiconductor material is a material having a band gap value strictly greater than zero and less than or equal to 6.5 electron volts (eV). The expression “forbidden band value” should be understood as being the value of the forbidden band between the valence band and the conduction band of the material.
La bande de valence est définie comme étant, parmi les bandes d’énergie qui sont autorisées pour les électrons dans le matériau, la bande qui présente l’énergie la plus élevée tout en étant complètement remplie à une température inférieure ou égale à 20 Kelvin (K). The valence band is defined as being, among the energy bands that are allowed for the electrons in the material, the band that has the highest energy while being completely filled at a temperature of 20 Kelvin or less ( K).
Un premier niveau d’énergie est défini pour chaque bande de valence. Le premier niveau d’énergie est le niveau d’énergie le plus élevé de la bande de valence. A first energy level is defined for each valence band. The first energy level is the highest energy level in the valence band.
La bande de conduction est définie comme étant, parmi les bandes d’énergie qui sont autorisées pour les électrons dans le matériau, la bande qui présente l’énergie la plus faible tout en n’étant pas complètement remplie à une température inférieure ou égale à 20 K. The conduction band is defined as being, among the energy bands which are allowed for the electrons in the material, the band which has the lowest energy while not being completely filled at a temperature less than or equal to 20 K.
Un deuxième niveau d’énergie est défini pour chaque bande de conduction. Le deuxième niveau d’énergie est le niveau d’énergie le moins élevé de la bande de conduction. A second energy level is defined for each conduction band. The second energy level is the lowest energy level in the conduction band.
Ainsi, chaque valeur de bande interdite est mesurée entre le premier niveau d’énergie et le deuxième niveau d’énergie du matériau. Thus, each band gap value is measured between the first energy level and the second energy level of the material.
Un semi-conducteur à bande interdite directe constitue un exemple de matériau semi-conducteur. Un matériau est considéré comme présentant une « bande interdite directe » lorsque le minimum de la bande de conduction et le maximum de la bande de valence correspondent à une même valeur de quantité de mouvement de porteurs de charge. Un matériau est considéré comme présentant une « bande interdite indirecte » lorsque le minimum de la bande de conduction et le maximum de la bande de valence correspondent à différentes valeurs de quantité de mouvement de porteurs de charge. A direct bandgap semiconductor is an example of a semiconductor material. A material is considered to have a “direct bandgap” when the minimum of the conduction band and the maximum of the valence band correspond to the same value of momentum of charge carriers. A material is considered to have an "indirect band gap" when the minimum of the conduction band and the maximum of the valence band correspond to different values of momentum of charge carriers.
Chaque matériau semi-conducteur est susceptible d’être choisi, par exemple, parmi l’ensemble formé des semi-conducteurs lll-V, notamment des nitrures d’éléments III, des semi-conducteurs ll-VI, ou encore des semi-conducteurs IV-IV. Each semiconductor material can be chosen, for example, from the set formed by semiconductors III-V, in particular nitrides of elements III, semiconductors II-VI, or even semiconductors. IV-IV.
Les semi-conducteurs lll-V comportent notamment InAs, GaAs, AlAs et leurs alliages, InP, GaP, AIP et leurs alliages, et les nitrures d’éléments III, qui sont AIN, GaN, InN et leurs alliages tels d’AIGaN ou encore InGaN. III-V semiconductors include in particular InAs, GaAs, AlAs and their alloys, InP, GaP, AIP and their alloys, and element III nitrides, which are AIN, GaN, InN and their alloys such as AIGaN or still InGaN.
Les semi-conducteurs ll-VI comportent notamment CdTe, HgTe, CdSe, HgSe, et leurs alliages. The II-VI semiconductors include in particular CdTe, HgTe, CdSe, HgSe, and their alloys.
Les semi-conducteurs IV-IV comportent notamment le diamant, Si, Ge et leurs alliages. IV-IV semiconductors include in particular diamond, Si, Ge and their alloys.
Le premier matériau semi-conducteur est, par exemple, AIN ou AIGaN, notamment lorsque le rayonnement est un rayonnement ultraviolet. En variante, le premier matériau semi-conducteur est, par exemple, GaN, ou encore un semi-conducteur lll-V. The first semiconductor material is, for example, AIN or AIGaN, in particular when the radiation is ultraviolet radiation. As a variant, the first semiconductor material is, for example, GaN, or else a III-V semiconductor.
Le premier matériau présente un dopage d’un premier type. The first material exhibits a doping of a first type.
Le premier type de dopage est choisi parmi le dopage de type p et le dopage de type n. Par exemple, le premier type de dopage est le dopage de type p. The first type of doping is chosen from p-type doping and n-type doping. For example, the first type of doping is p-type doping.
Le dopage se définit comme la présence, dans un matériau, d’impuretés apportant des porteurs de charges libres. Les impuretés sont, par exemple, des atomes d’un élément qui n’est pas naturellement présent dans le matériau. Doping is defined as the presence, in a material, of impurities providing free charge carriers. Impurities are, for example, atoms of an element that is not naturally present in the material.
Lorsque les impuretés augmentent la densité volumique de trous dans le matériel, par rapport à du matériel non dopé, le dopage est de type p. Par exemple, une couche de nitrure de gallium, GaN, ou de nitrure de gallium et d’aluminium, AIGaN, est dopée p en ajoutant des atomes de magnésium (Mg). When the impurities increase the volume density of holes in the material, compared to undoped material, the doping is p-type. For example, a layer of gallium nitride, GaN, or gallium aluminum nitride, AIGaN, is p-doped by adding magnesium (Mg) atoms.
Lorsque le premier matériau semi-conducteur est AIN, le dopage de type p est, par exemple, obtenu par l’ajout d’atomes d’indium In et de magnésium Mg. When the first semiconductor material is AIN, the p-type doping is, for example, obtained by adding atoms of indium In and magnesium Mg.
Lorsque les impuretés augmentent la densité volumique d’électrons libres dans le matériau, par rapport au matériau non dopé, le dopage est de type n. Par exemple, une couche de nitrure de gallium, GaN, est dopée n en ajoutant des atomes de silicium (Si). When the impurities increase the volume density of free electrons in the material, relative to the undoped material, the doping is n-type. For example, a layer of gallium nitride, GaN, is n-doped by adding silicon (Si) atoms.
Une épaisseur de la première portion 40, mesurée selon la direction d’empilement D, est par exemple comprise entre 50 nm et 5 pm. A thickness of the first portion 40, measured along the stacking direction D, is for example between 50 nm and 5 μm.
Optionnellement, la première portion 40 comporte une couche bloqueuse d’électrons dopée p et réalisée en un matériau semi-conducteur présentant une bande interdite strictement supérieure à la bande interdite du deuxième matériau. La couche bloqueuse d’électrons est, par exemple, réalisée en AIGaN. La couche bloqueuse d’électrons est, notamment, délimitée selon la direction d’empilement D par la portion d’émission 45. Optionally, the first portion 40 comprises a p-doped electron blocking layer made of a semiconductor material having a forbidden band strictly greater than the forbidden band of the second material. The electron blocking layer is, for example, made of AIGaN. The electron blocking layer is, in particular, delimited along the stacking direction D by the emission portion 45.
La portion d’émission 45 est configurée pour émettre le rayonnement lorsqu’un courant électrique traverse la diode électroluminescente 20. The emitting portion 45 is configured to emit radiation when an electric current passes through the light emitting diode 20.
La portion d’émission 45 est réalisée en un matériau d’émission. Le matériau d’émission est un matériau semi-conducteur. En particulier, le matériau d’émission présente une valeur de bande interdite strictement inférieure à la valeur de bande interdite du premier matériau semi-conducteur. Par exemple, lorsque le premier matériau est AIN, le matériau semi-conducteur d’émission est AIGaN. The emission portion 45 is made of an emission material. The emission material is a semiconductor material. In particular, the emission material has a band gap value that is strictly less than the band gap value of the first semiconductor material. For example, when the first material is AIN, the emission semiconductor material is AIGaN.
Optionnellement, la portion d’émission 45 comporte un puits quantique ou un ensemble de puits quantiques. Optionally, the emission portion 45 comprises a quantum well or a set of quantum wells.
Un puits quantique est une structure dans laquelle un confinement quantique se produit, dans une direction, pour au moins un type de porteurs de charges. Les effets du confinement quantique se produisent lorsque la dimension de la structure le long de cette direction devient comparable à ou plus petite que la longueur d’onde de De Broglie des porteurs, lesquels sont généralement des électrons et/ou à des trous, conduisant à des niveaux d’énergie appelés « sous-bandes d’énergie ». A quantum well is a structure in which quantum confinement occurs, in one direction, for at least one type of charge carriers. The effects of quantum confinement occur when the dimension of the structure along this direction becomes comparable to or smaller than the De Broglie wavelength of carriers, which are usually electrons and / or holes, leading to levels of d 'energy called "energy sub-bands".
Dans un tel puits quantique, les porteurs ne peuvent présenter que des valeurs d’énergie discrètes mais sont généralement aptes à se déplacer à l’intérieur d’un plan perpendiculaire à la direction dans laquelle le confinement se produit. Les valeurs d’énergie disponibles pour les porteurs, également appelées « niveaux d’énergie », augmentent lorsque les dimensions du puits quantique diminuent le long de la direction dans laquelle le confinement se produit. In such a quantum well, carriers can exhibit only discrete energy values but are generally able to move within a plane perpendicular to the direction in which confinement occurs. The energy values available to carriers, also called "energy levels", increase as the dimensions of the quantum well decrease along the direction in which confinement occurs.
En mécanique quantique, la « longueur d’onde de De Broglie » est la longueur d’onde d’une particule lorsque la particule est considérée comme une onde. La longueur d’onde de De Broglie des électrons est également appelée « longueur d’onde électronique ». La longueur d’onde de De Broglie d’un porteur de charge dépend du matériau dont est constitué le puits quantique. In quantum mechanics, the "De Broglie wavelength" is the wavelength of a particle when the particle is considered a wave. The De Broglie wavelength of electrons is also called the "electron wavelength". The De Broglie wavelength of a charge carrier depends on the material of which the quantum well is made.
Une couche émettrice dont l’épaisseur est strictement inférieure au produit de la longueur d’onde électronique des électrons dans le matériau semi-conducteur dont la couche émettrice est constituée et de cinq est un exemple de puits quantique. An emitter layer whose thickness is strictly less than the product of the electronic wavelength of the electrons in the semiconductor material that the emitter layer is made of and five is an example of a quantum well.
Un autre exemple de puits quantique est une couche émettrice dont l’épaisseur est strictement inférieure au produit de la longueur d’onde de De Broglie d’excitons dans le matériau semi-conducteur dont la couche émettrice est constituée et de cinq. Un exciton est une quasi-particule comprenant un électron et un trou. Another example of a quantum well is an emitting layer whose thickness is strictly less than the product of the De Broglie wavelength of excitons in the semiconductor material of which the emitting layer is made and five. An exciton is a quasi-particle comprising an electron and a hole.
En particulier, un puits quantique présente souvent une épaisseur comprise entre 1 nm et 200 nm. In particular, a quantum well often has a thickness of between 1 nm and 200 nm.
Le ou les puits quantique(s) sont par exemple constitués par une couche de matériau d’émission interposée entre deux couches d’un matériau, par exemple du premier matériau semi-conducteur, présentant une valeur de bande interdite strictement supérieure à celle du matériau d’émission. The quantum well (s) are for example constituted by a layer of emission material interposed between two layers of a material, for example of the first semiconductor material, having a band gap value strictly greater than that of the material. resignation.
Par exemple, la portion d’émission 45 comporte une ou plusieurs couche(s) du matériau d’émission, notamment d’AIGaN, interposée(s) entre des couches d’AIN ou d’un AIGaN à plus forte teneur en aluminium que le matériau d’émission. For example, the emission portion 45 comprises one or more layer (s) of the emission material, in particular of AIGaN, interposed between layers of AIN or of an AIGaN with a higher aluminum content than the emission material.
En variante, lorsque le rayonnement est un rayonnement visible, le matériau d’émission est InGaN, et la ou les couche(s) d’InGaN est (sont) interposée(s) entre des couches de GaN. La portion d’émission 45 est, par exemple, non dopée. Toutefois, selon des variantes envisageables, la portion d’émission 45 est susceptible de présenter le premier ou le deuxième type de dopage. Alternatively, when the radiation is visible radiation, the emitting material is InGaN, and the InGaN layer (s) is (are) interposed between GaN layers. The emission portion 45 is, for example, undoped. However, according to possible variants, the emission portion 45 is capable of exhibiting the first or the second type of doping.
Selon un mode de réalisation, le matériau d’émission composant le ou les puit(s) quantique(s) est non dopé, et le matériau composant les couches enserrant le matériau d’émission présente un dopage du premier ou du deuxième type. According to one embodiment, the emission material making up the quantum well (s) is undoped, and the material making up the layers enclosing the emission material exhibits doping of the first or second type.
La deuxième portion 50 est interposée entre la portion d’émission 45 et le support 15, notamment entre la portion d’émission 45 et la couche de réflexion 35. The second portion 50 is interposed between the emission portion 45 and the support 15, in particular between the emission portion 45 and the reflection layer 35.
La deuxième portion 50 est réalisée en un deuxième matériau semi-conducteur.The second portion 50 is made of a second semiconductor material.
Le deuxième matériau semi-conducteur présente une valeur de bande interdite strictement supérieure à la valeur de bande interdite du matériau d’émission. Par exemple, le deuxième matériau semi-conducteur est identique, au type de dopage près, au premier matériau. En particulier, le deuxième matériau semi-conducteur est AIN. En variante, le deuxième matériau est AIGaN, ou encore GaN. The second semiconductor material has a band gap value that is strictly greater than the band gap value of the emission material. For example, the second semiconductor material is identical, except for the type of doping, to the first material. In particular, the second semiconductor material is AIN. As a variant, the second material is AIGaN, or even GaN.
Le deuxième matériau semi-conducteur présente un deuxième type de dopage différent du premier type de dopage. Le deuxième type de dopage est choisi parmi le dopage de type n et le dopage de type p. Par exemple, le deuxième type de dopage est le dopage de type n. The second semiconductor material has a second type of doping different from the first type of doping. The second type of doping is chosen from n-type doping and p-type doping. For example, the second type of doping is n-type doping.
La deuxième portion 50 présente une épaisseur, mesurée selon la direction d’empilement D, comprise par exemple entre 50 nm et 1 pm. The second portion 50 has a thickness, measured along the stacking direction D, for example between 50 nm and 1 μm.
Lorsque la diode électroluminescente 20 comporte un ensemble de structures tridimensionnelles, la diode électroluminescente 20 est, par exemple, formée par la réunion d’un ensemble de diodes électroluminescentes élémentaires, chaque diode électroluminescente élémentaire comportant une structure tridimensionnelle dont une partie forme une partie de la première portion 40, une autre partie forme une partie de la portion d’émission 45 et une partie forme une partie de la deuxième portion 50. When the light-emitting diode 20 comprises a set of three-dimensional structures, the light-emitting diode 20 is, for example, formed by the joining of a set of elementary light-emitting diodes, each elementary light-emitting diode comprising a three-dimensional structure, a part of which forms part of the first portion 40, another part forms a part of the emission portion 45 and a part forms a part of the second portion 50.
Par exemple, chaque diode électroluminescente élémentaire est un nanofil comportant une portion primaire 55 (ou « base »), une portion intermédiaire 60 et une portion secondaire 65 (ou « portion d’extrémité »), superposées dans cet ordre selon la direction d’empilement D. For example, each elementary light-emitting diode is a nanowire comprising a primary portion 55 (or “base”), an intermediate portion 60 and a secondary portion 65 (or “end portion”), superimposed in this order in the direction of. stacking D.
La portion primaire 55 est délimitée selon la direction d’empilement D par la couche fenêtre 25 et par la portion intermédiaire 60. La portion primaire 55 est réalisée en le premier matériau semi-conducteur. The primary portion 55 is delimited along the stacking direction D by the window layer 25 and by the intermediate portion 60. The primary portion 55 is made of the first semiconductor material.
La première portion 40 est formée par l’ensemble des portions primaires 55 des différentes diodes électroluminescentes élémentaires. The first portion 40 is formed by all of the primary portions 55 of the various elementary light-emitting diodes.
Chaque portion primaire 55 s’étend selon la direction d’empilement D. Chaque portion primaire 55 est, par exemple, cylindrique. Il est entendu par « cylindrique » que chaque portion primaire 55 présente une section uniforme dans tout plan perpendiculaire à la direction d’empilement D. La section est, par exemple, circulaire, ou encore hexagonale. Each primary portion 55 extends in the direction of stacking D. Each primary portion 55 is, for example, cylindrical. It is understood by “cylindrical” that each primary portion 55 has a uniform section in any plane perpendicular to the stacking direction D. The section is, for example, circular, or even hexagonal.
Les portions primaires 55 sont, par exemple, séparées les unes des autres. En particulier, chaque portion primaire 55 est distante des autres portions primaires 55. The primary portions 55 are, for example, separated from each other. In particular, each primary portion 55 is remote from the other primary portions 55.
La portion intermédiaire 60 est délimitée selon la direction d’empilement D par la portion primaire 55 et la portion secondaire 65. La portion intermédiaire 60 est réalisée en le matériau semi-conducteur d’émission. The intermediate portion 60 is delimited along the stacking direction D by the primary portion 55 and the secondary portion 65. The intermediate portion 60 is made of the semiconductor emission material.
La portion d’émission 45 est formée par l’ensemble des portions intermédiaires 60 des différentes diodes électroluminescentes élémentaires. The emission portion 45 is formed by all of the intermediate portions 60 of the various elementary light-emitting diodes.
Chaque portion intermédiaire 60 est, par exemple, cylindrique. La section de la portion intermédiaire 60 dans un plan perpendiculaire à la direction d’empilement D est, par exemple, circulaire, ou encore hexagonale. Each intermediate portion 60 is, for example, cylindrical. The section of the intermediate portion 60 in a plane perpendicular to the stacking direction D is, for example, circular, or even hexagonal.
Les portions intermédiaires 60 sont, par exemple, séparées les unes des autres. En particulier, chaque portion intermédiaire 60 est distante des autres portion intermédiaire 60. The intermediate portions 60 are, for example, separated from each other. In particular, each intermediate portion 60 is distant from the other intermediate portion 60.
La portion secondaire 65 est délimitée selon la direction d’empilement D par la portion intermédiaire 60 et par le support 15, notamment par la couche de réflexion 35. La portion secondaire 65 est réalisée en le deuxième matériau semi-conducteur. The secondary portion 65 is delimited along the stacking direction D by the intermediate portion 60 and by the support 15, in particular by the reflection layer 35. The secondary portion 65 is made of the second semiconductor material.
La deuxième portion 50 est formée par l’ensemble des portions secondaires 65 des différentes diodes électroluminescentes élémentaires. The second portion 50 is formed by all of the secondary portions 65 of the various elementary light-emitting diodes.
Chaque portion secondaire 65 est, par exemple, cylindrique. La section de la portion secondaire 65 dans un plan perpendiculaire à la direction d’empilement D est, par exemple, circulaire, ou encore hexagonale. Each secondary portion 65 is, for example, cylindrical. The section of the secondary portion 65 in a plane perpendicular to the stacking direction D is, for example, circular, or even hexagonal.
En variante, comme visible sur la figure 1 , chaque portion secondaire 65 est conique ou pyramidale. En particulier, une dimension de la portion secondaire 65 dans un plan perpendiculaire à la direction d’empilement 65 augmente en s’éloignant de la portion intermédiaire 60. Notamment, les portions secondaires 65 des différentes diodes électroluminescentes élémentaires sont solidaires les unes des autres, et présentent une continuité de matière les unes aux autres. As a variant, as can be seen in FIG. 1, each secondary portion 65 is conical or pyramidal. In particular, a dimension of the secondary portion 65 in a plane perpendicular to the stacking direction 65 increases as it moves away from the intermediate portion 60. In particular, the secondary portions 65 of the various elementary light-emitting diodes are integral with one another, and present a continuity of material to each other.
La couche fenêtre 25 est prévue pour être traversée par le rayonnement. En outre, la couche fenêtre 25 est électriquement conductrice. The window layer 25 is designed to be traversed by the radiation. Further, window layer 25 is electrically conductive.
La couche fenêtre 25 est, notamment, monocristalline. En variante, la couche fenêtre est polycristalline ou nanocristalline, c’est-à-dire formée de cristaux multiples, chaque cristal présentant des dimensions nanométriques. La couche fenêtre 25 est réalisée en un matériau semi-conducteur, appelé dans la suite matériau de substrat. Window layer 25 is, in particular, monocrystalline. As a variant, the window layer is polycrystalline or nanocrystalline, that is to say formed of multiple crystals, each crystal having nanometric dimensions. The window layer 25 is made of a semiconductor material, hereinafter referred to as the substrate material.
Le matériau de substrat est transparent au rayonnement. En particulier, le matériau de substrat présente une valeur de bande interdite strictement supérieure à la valeur de bande interdite du matériau d’émission. Optionnellement, le matériau de substrat présente une valeur de bande interdite strictement supérieure à la valeur de bande interdite du premier matériau. The substrate material is transparent to radiation. In particular, the substrate material has a band gap value that is strictly greater than the band gap value of the emission material. Optionally, the substrate material has a band gap value that is strictly greater than the band gap value of the first material.
Le matériau de substrat est, par exemple, le diamant. En variante, le matériau de substrat est IΆIN. The substrate material is, for example, diamond. Alternatively, the substrate material is IΆIN.
Le matériau de substrat présente un dopage du premier type. The substrate material exhibits doping of the first type.
Une résistivité du matériau de substrat est, par exemple, comprise entre 103 Ohm - centimètre (W.ah) et 104 Q.cm. A resistivity of the substrate material is, for example, between 10 3 Ohm - centimeter (W.ah) and 10 4 Q.cm.
La couche fenêtre 25 présente une épaisseur, mesurée selon la direction d’empilement D, comprise entre 10 nm et 1 pm. The window layer 25 has a thickness, measured along the stacking direction D, of between 10 nm and 1 µm.
La couche fenêtre 25 est, par exemple, électriquement connectée au circuit de commande. Window layer 25 is, for example, electrically connected to the control circuit.
Le circuit de commande est configuré pour générer un courant électrique traversant la diode électroluminescente 20. En particulier, le courant électrique traverse successivement la couche de réflexion 35, la diode électroluminescente 20 et la couche fenêtre 25. The control circuit is configured to generate an electric current passing through the light emitting diode 20. In particular, the electric current successively passes through the reflection layer 35, the light emitting diode 20 and the window layer 25.
Le courant électrique est propre à causer l’émission du rayonnement par la diode électroluminescente 20 lorsque le courant électrique traverse la diode électroluminescente 20. The electric current is capable of causing the emission of radiation by the light emitting diode 20 when the electric current passes through the light emitting diode 20.
Un procédé de fabrication du dispositif d’émission 10 va maintenant être décrit en référence à la figure 2, qui présente un ordinogramme des étapes de ce procédé. A method of manufacturing the transmission device 10 will now be described with reference to Figure 2, which shows a flowchart of the steps of this method.
Le procédé de fabrication comporte une étape 100 de fourniture, une étape 110 d’implantation, une étape 120 de formation, une étape 130 de fixation et une étape 140 de rupture. The manufacturing process includes a supply step 100, an implantation step 110, a training step 120, a fixing step 130 and a breaking step 140.
Lors de l’étape de fourniture 100, un substrat 70 est fourni. In the supply step 100, a substrate 70 is provided.
Le substrat 70 est notamment visible sur la figure 3. The substrate 70 is in particular visible in FIG. 3.
Le substrat 70 est réalisé au moins partiellement en le matériau de substrat. En particulier, le substrat 70 comporte au moins une portion 75 réalisée en le matériau de substrat. The substrate 70 is made at least partially of the substrate material. In particular, the substrate 70 comprises at least one portion 75 made of the substrate material.
La portion 75 est, par exemple, une couche de matériau de substrat portée par une plaque 80 (ou « wafer ») servant de support à la couche. Par exemple, la couche 75 de matériau de substrat est portée par une plaque 80 réalisée en le même matériau que le matériau de substrat, la plaque 80 se différenciant par le fait que le matériau composant la plaque 80 est non dopé ou présente un dopage moindre que le matériau de substrat. Notamment, la plaque 80 est réalisée en diamant non dopé ou faiblement dopé. The portion 75 is, for example, a layer of substrate material carried by a plate 80 (or “wafer”) serving as a support for the layer. For example, the layer 75 of substrate material is carried by a plate 80 made of the same material as the substrate material, the plate 80 being differentiated by the fact that the material making up the plate 80 is undoped or has less doping. as the substrate material. In particular, the plate 80 is made of undoped or lightly doped diamond.
En variante, le substrat 70 est intégralement réalisé en le matériau de substrat. Dans ce cas, la portion 75 forme l’intégralité du substrat 70. Alternatively, the substrate 70 is made entirely from the substrate material. In this case, the portion 75 forms the entirety of the substrate 70.
La portion 75 est, par exemple, monocristalline. Par exemple, la couche 75 et la plaque 80 sont chacune monocristalline. Portion 75 is, for example, monocrystalline. For example, layer 75 and plate 80 are each single crystal.
Selon un mode de réalisation, le substrat 70 est monocristallin. According to one embodiment, the substrate 70 is monocrystalline.
Le substrat présente une première face 85. The substrate has a first face 85.
La première face 85 est, par exemple, plane. The first face 85 is, for example, flat.
La première face 85 délimite le substrat 70, notamment la portion 75 de matériau de substrat, selon une direction N normale à la première face 85. En particulier, la couche 75 s’étend dans un plan perpendiculaire à la direction normale N. The first face 85 delimits the substrate 70, in particular the portion 75 of substrate material, in a direction N normal to the first face 85. In particular, the layer 75 extends in a plane perpendicular to the normal direction N.
Selon un mode de réalisation, la première face 85 comporte un masque c’est-à-dire une couche couvrant partiellement la première face 85. En particulier, le masque est réalisé en un matériau empêchant le dépôt du premier matériau sur le masque, de manière à ce que, comme il apparaîtra par la suite, le dépôt de premier matériau n’ait lieu que sur les portions de la première face 85 dépourvues de masque. Le masque est, par exemple, réalisé en nitrure de titane TiN, ou encore en nitrure de Silicium (SixNy), en T1O2, en S1O2 ou en graphène. According to one embodiment, the first face 85 comprises a mask, that is to say a layer partially covering the first face 85. In particular, the mask is made of a material preventing the deposition of the first material on the mask, of so that, as will appear subsequently, the deposition of the first material takes place only on the portions of the first face 85 without a mask. The mask is, for example, made of titanium nitride TiN, or else of silicon nitride (Si x N y ), of T1O2, of S1O2 or of graphene.
Lors de l’étape d’implantation 110, un ensemble d’atomes est implanté dans le matériau de substrat. In the implantation step 110, a set of atoms are implanted in the substrate material.
Il est notamment entendu par « implanter » que des atomes ou des ions sont accélérés, par exemple par un champ électrique ou magnétique, et propulsés en direction du substrat 70, notamment en direction de la première face 85, de manière à ce que les atomes soient enterrés dans le substrat 70. It is in particular understood by “implant” that atoms or ions are accelerated, for example by an electric or magnetic field, and propelled in the direction of the substrate 70, in particular in the direction of the first face 85, so that the atoms are buried in the substrate 70.
Les atomes sont, par exemple, des atomes d’hydrogène. Toutefois, d’autres types d’atomes sont susceptibles d’être utilisés. La densité surfacique d’atomes d’hydrogène est, par exemple, comprise entre 1015 et 1018 cnr2. La profondeur d’implantation est, par exemple, comprise entre 10 nm et 1 pm. Atoms are, for example, hydrogen atoms. However, other types of atoms are likely to be used. The surface density of hydrogen atoms is, for example, between 10 15 and 10 18 cnr 2 . The implantation depth is, for example, between 10 nm and 1 μm.
Les atomes sont, notamment, implantés dans le matériau de substrat à travers la première face 85. A l’issue de l’étape d’implantation 110, il est obtenu, dans le matériau de substrat, notamment dans la portion 75, une portion fragilisée 90, une portion de surface 92 et une portion interne 95. The atoms are, in particular, implanted in the substrate material through the first face 85. At the end of the implantation step 110, there is obtained, in the substrate material, in particular in the portion 75, a weakened portion 90, a surface portion 92 and an internal portion 95.
La portion de matériau de substrat 75 est formée par la réunion de la portion fragilisée 90, de la portion de surface 92 et de la portion interne 95. The portion of substrate material 75 is formed by joining the embrittled portion 90, the surface portion 92 and the inner portion 95.
La portion fragilisée 90 est la portion du matériau de substrat 75 dans laquelle les atomes implantés sont présents. The embrittled portion 90 is the portion of the substrate material 75 in which the implanted atoms are present.
La portion fragilisée 90 s’étend parallèlement à la première face 85, donc dans un plan perpendiculaire à la direction normale N. The weakened portion 90 extends parallel to the first face 85, therefore in a plane perpendicular to the normal direction N.
En effet, si les atomes implantés sont projetés sur la première face 85, au cours de l’étape d’implantation 110, avec une vitesse identique pour tous les atomes, la profondeur à laquelle chaque atome est implanté, mesurée selon la direction normale N à partir de la première face 85, est identique pour tous les atomes. Ainsi, une portion fragilisée 90 s’étendant parallèlement à la première face 85 est obtenue. Indeed, if the implanted atoms are projected onto the first face 85, during the implantation step 110, with an identical speed for all the atoms, the depth at which each atom is implanted, measured according to the normal direction N from the first face 85, is the same for all atoms. Thus, a weakened portion 90 extending parallel to the first face 85 is obtained.
La profondeur d’implantation des atomes est comprise entre 10 nm et 1 pm. En particulier, la profondeur d’implantation est égale à l’épaisseur de la couche fenêtre 25 qu’il est souhaité obtenir à l’issue du procédé de fabrication. The implantation depth of atoms is between 10 nm and 1 pm. In particular, the implantation depth is equal to the thickness of the window layer 25 that it is desired to obtain at the end of the manufacturing process.
La portion fragilisée 90 sépare la portion de surface 92 de la portion interne 95.The weakened portion 90 separates the surface portion 92 from the internal portion 95.
La portion de surface 92 est interposée selon la direction normale N entre la portion fragilisée 90 et la portion interne 95. En d’autres termes, la portion interne 95 est formée par l’ensemble des portions de matériau de substrat qui sont situées à une profondeur, par rapport à la première face 85, strictement supérieure à la profondeur d’implantation des atomes. The surface portion 92 is interposed in the normal direction N between the weakened portion 90 and the internal portion 95. In other words, the internal portion 95 is formed by all of the portions of substrate material which are located at a distance. depth, relative to the first face 85, strictly greater than the implantation depth of the atoms.
Lors de l’étape de formation 120, la diode électroluminescente 20 est formée sur la première face 85. En particulier, le premier matériau, le matériau d’émission et le deuxième matériau sont déposés dans cet ordre sur la première face 85 de manière à obtenir la diode électroluminescente 20. During the forming step 120, the light emitting diode 20 is formed on the first face 85. In particular, the first material, the emitting material and the second material are deposited in this order on the first face 85 so as to get the light emitting diode 20.
La diode électroluminescente 20 est, par exemple, formée par dépôt chimique en phase vapeur (en Anglais « Chemical vapor déposition », ou CVD), ou encore par épitaxie par jets moléculaires (en Anglais « Molecular Beam Epitaxy »). The light-emitting diode 20 is, for example, formed by chemical vapor deposition (in English "Chemical vapor deposition", or CVD), or by molecular beam epitaxy (in English "Molecular Beam Epitaxy").
A l’issue de l’étape de formation 120, la direction d’empilement D de la diode électroluminescente 20 est confondue avec la direction normale N. At the end of the forming step 120, the stacking direction D of the light emitting diode 20 coincides with the normal direction N.
A l’issue de l’étape de formation 120, la diode électroluminescente 20 est délimitée par la première face 85 et par une face d’extrémité 150 de la diode électroluminescente. After the forming step 120, the light emitting diode 20 is bounded by the first face 85 and by an end face 150 of the light emitting diode.
La première portion 40 est interposée entre la première face 85 et la portion d’émission 45 selon la direction normale N. La première portion 40 est, notamment, délimitée selon la direction normale N par la première face 85 et par la portion d’émission 45. En particulier, la première portion 40 est solidaire de la portion de surface 92. The first portion 40 is interposed between the first face 85 and the emission portion 45 in the normal direction N. The first portion 40 is, in particular, delimited in the normal direction N by the first face 85 and by the emission portion 45. In particular, the first portion 40 is integral with the surface portion 92.
Par exemple, la première portion croît en épitaxie sur la première face 85. For example, the first portion grows epitaxially on the first face 85.
De manière connue en soi, les structures tridimensionnelles composant la diode électroluminescente sont obtenues par le dépôt du premier matériau sur les portions de la première face 85 dépourvues de masque, le premier matériau n’étant pas déposé sur le masque. Ainsi, des portions primaires 55 séparées les unes des autres et s’étendant selon la direction normale N sont obtenues. In a manner known per se, the three-dimensional structures making up the light-emitting diode are obtained by depositing the first material on the portions of the first face 85 without a mask, the first material not being deposited on the mask. Thus, primary portions 55 separated from each other and extending in the normal direction N are obtained.
En variante, les conditions de dépôt, notamment de température, pendant l’étape de formation 120, sont choisies pour que la croissance du premier matériau ait lieu naturellement sous forme de colonnes séparées les unes des autres. As a variant, the deposition conditions, in particular temperature, during the formation step 120, are chosen so that the growth of the first material takes place naturally in the form of columns separated from each other.
Une fois la première portion 40 formée, la portion d’émission 45 et la deuxième portion 50 sont déposées sur les colonnes formant la première portion 40, et ont naturellement tendance à conserver une croissance tridimensionnelle. Once the first portion 40 has been formed, the emission portion 45 and the second portion 50 are deposited on the columns forming the first portion 40, and naturally tend to maintain three-dimensional growth.
Optionnellement, l’étape de formation 120 comporte une étape de coalescence des portions secondaires 65 formant la deuxième portion 50. Par exemple, les conditions, notamment la température du substrat 70, pendant le dépôt du deuxième matériau sont choisies pour que la dimension latérale des portions secondaires 65 augmente en s’éloignant des portions intermédiaires 60 jusqu’à ce que les portions secondaires 65 viennent en contact les unes avec les autres puis fusionnent pour former une deuxième portion 50 monobloc. Optionally, the forming step 120 comprises a step of coalescing the secondary portions 65 forming the second portion 50. For example, the conditions, in particular the temperature of the substrate 70, during the deposition of the second material are chosen so that the lateral dimension of the secondary portions 65 increase away from the intermediate portions 60 until the secondary portions 65 come into contact with each other and then merge to form a second integral portion 50.
En variante ou en complément, l’étape de formation 120 comporte une étape de planarisation. As a variant or in addition, the training step 120 includes a planarization step.
L’étape de planarisation comporte, l’injection d’un matériau de remplissage dans l’espace entre les nanostructures, notamment les nanofils, formant la diode électroluminescente. The planarization step involves the injection of a filling material into the space between the nanostructures, in particular the nanowires, forming the light emitting diode.
Le matériau de remplissage est transparent au rayonnement. En outre, le matériau de remplissage est électriquement isolant. Le matériau de remplissage est, par exemple, l’alumine AI2O3. The filling material is transparent to radiation. In addition, the filling material is electrically insulating. The filling material is, for example, alumina Al 2 O 3 .
Postérieurement à l’injection et/ou à la coalescence, la face d’extrémité 150 de la diode électroluminescente 20 est planarisée, par exemple par polissage mécanique ou mécano-chimique. En effet, la face d’extrémité 150 est susceptible de présenter, à l’issue du dépôt du deuxième matériau, une rugosité excessive, notamment lorsque la diode électroluminescente 20 comporte un ensemble de structures tridimensionnelles, puisque la hauteur de ces structures est susceptible de varier d’une structure à l’autre à cause de variations du diamètre de ces structures ou encore de variations locales de la densité de structures. After the injection and / or the coalescence, the end face 150 of the light-emitting diode 20 is planarized, for example by mechanical or mechanical-chemical polishing. In fact, the end face 150 is liable to exhibit, after the deposition of the second material, excessive roughness, in particular when the light-emitting diode 20 comprises a set of three-dimensional structures, since the height of these structures is liable to increase. vary from one structure to another because of variations in the diameter of these structures or even local variations in the density of structures.
Lors de l’étape de fixation 130, la face d’extrémité 150 de la diode électroluminescente 20 est fixée à une face, appelée deuxième face 155, du support 15, comme représenté sur la figure 4. En particulier, la deuxième face 155 est une face délimitant la couche de réflexion 35 selon la direction d’empilement D. During the fixing step 130, the end face 150 of the light-emitting diode 20 is fixed to a face, called the second face 155, of the support 15, as shown in FIG. 4. In particular, the second face 155 is. a face delimiting the reflection layer 35 along the stacking direction D.
Dans le cas d’un support 15 bi-couches, les faces 150 et 155 sont, par exemple, fixées l’une à l’autre en déposant une couche métallique, par exemple une couche d’aluminium (par exemple par évaporation ou par « électron beam physical vapor déposition ») sur la face 150, puis en soudant le support 15 à la couche d’aluminium, par exemple à l’aide d’un métal de brasure interposé entre le support 15 et la face 150. In the case of a two-layer support 15, the faces 150 and 155 are, for example, fixed to one another by depositing a metal layer, for example a layer of aluminum (for example by evaporation or by “Electron beam physical vapor deposition”) on the face 150, then by welding the support 15 to the aluminum layer, for example using a brazing metal interposed between the support 15 and the face 150.
Lors de l’étape de rupture 140, la portion fragilisée 90 est rompue de manière à séparer la portion de surface 92 de la portion interne 95. Ainsi, la portion de surface 92, séparée du reste du substrat 70 et solidaire de la première portion 40 de la diode électroluminescente, forme la couche fenêtre 25. La rupture de la portion fragilisée 90 est notamment visible sur la figure 5. During the breaking step 140, the weakened portion 90 is broken so as to separate the surface portion 92 from the internal portion 95. Thus, the surface portion 92, separated from the rest of the substrate 70 and integral with the first portion 40 of the light-emitting diode, forms the window layer 25. The rupture of the weakened portion 90 is visible in particular in FIG. 5.
La portion fragilisée 90 est, par exemple, rompue en chauffant le substrat 70 à une température et pendant une durée propres à provoquer dans la portion fragilisée 90 la formation de bulles d’un gaz formé par les atomes implantés. Les bulles formées causent ainsi la rupture de la portion fragilisée 90 et la séparation de la portion 75 de matériau de substrat le long de la portion fragilisée 90. The weakened portion 90 is, for example, broken by heating the substrate 70 to a temperature and for a period of time suitable for causing in the weakened portion 90 the formation of bubbles of a gas formed by the implanted atoms. The bubbles formed thus cause the embrittled portion 90 to rupture and the portion 75 of substrate material to separate along the embrittled portion 90.
En outre, à l’issue de l’étape de rupture 140, le circuit de commande est connecté électriquement à la portion de surface 92, formant la couche fenêtre 25, et/ ou à la couche de réflexion 25. In addition, at the end of the breaking step 140, the control circuit is electrically connected to the surface portion 92, forming the window layer 25, and / or to the reflection layer 25.
Grâce à l’invention, il est obtenu aisément une couche fenêtre 25 transparente au rayonnement. Notamment, cette couche fenêtre est susceptible d’être réalisée en un matériau ne se prêtant pas au dépôt sur la diode électroluminescente 20, par exemple en un matériau dont le dépôt est fait à des températures susceptibles d’endommager la diode électroluminescente 20. La plus grande variété de matériaux ainsi permis permet notamment l’utilisation de matériaux de substrat, tels que le diamant, à la fois conducteurs et transparent au rayonnement. Thanks to the invention, a window layer 25 transparent to radiation is easily obtained. In particular, this window layer is capable of being made of a material which is not suitable for deposition on the light-emitting diode 20, for example of a material which is deposited at temperatures liable to damage the light-emitting diode 20. The most large variety of materials thus allowed allows in particular the use of substrate materials, such as diamond, both conductive and transparent to radiation.
Par ailleurs, un même substrat 70 est susceptible d’être utilisé un grand nombre de fois, une faible épaisseur de matériau de substrat (formant la portion de surface 92) étant retirée à chaque fois. Ainsi, un même substrat 70 peut servir à la croissance de nombreuses diodes 20 et à la fabrication de nombreux dispositifs émetteurs 10, ce qui est particulièrement intéressant dans le cas de substrats 70 difficiles à obtenir, par exemple dans le cas de substrats 70 en AIN ou en AIN sur silicium. Moreover, the same substrate 70 is capable of being used a large number of times, a small thickness of substrate material (forming the surface portion 92) being removed each time. Thus, the same substrate 70 can be used for the growth of numerous diodes 20 and for the manufacture of numerous emitter devices 10, which is particularly advantageous in the case of substrates 70 which are difficult to obtain, for example in the case of substrates 70 made of AIN or of AIN on silicon.
De plus, la rupture de la portion fragilisée 90 génère une rugosité de surface de la face de la couche fenêtre 25 qui est opposée à la diode électroluminescente 20, c’est-à- dire la face à travers laquelle le rayonnement est prévu pour sortir de la couche fenêtre 25. Cette rugosité facilite l’extraction du rayonnement hors de la couche fenêtre 25 et augmente donc le rendement du dispositif 10. In addition, the rupture of the weakened portion 90 generates a surface roughness of the face of the window layer 25 which is opposite the light emitting diode 20, i.e. the face through which the radiation is intended to exit. of the window layer 25. This roughness facilitates the extraction of the radiation from the window layer 25 and therefore increases the efficiency of the device 10.
Une longueur caractéristique de la rugosité est, par exemple, comprise entre 0,1 et 30 fois un rapport entre, au numérateur, la longueur d’onde moyenne du rayonnement et, au numérateur, l’indice optique à cette longueur d’onde du matériau composant la couche fenêtre 25, cette gamme de longueurs caractéristiques permettant une bonne extraction du rayonnement. A characteristic length of the roughness is, for example, between 0.1 and 30 times a ratio between, in the numerator, the mean wavelength of the radiation and, in the numerator, the optical index at this wavelength of the material making up the window layer 25, this range of characteristic lengths allowing good extraction of the radiation.
En outre, la couche fenêtre 25 est susceptible d’être monocristalline si le substrat 70 utilisé comporte une portion 75 monocristalline. La transparence et/ou la conductivité électrique de la couche fenêtre 25 sont donc améliorées par rapport à des couches fenêtres 25 polycristallines. In addition, the window layer 25 is likely to be monocrystalline if the substrate 70 used has a monocrystalline portion 75. The transparency and / or the electrical conductivity of the window layer 25 are therefore improved compared to polycrystalline window layers 25.
Le diamant est notamment un matériau transparent sur une large gamme de longueurs d’ondes et susceptible d’être conducteur, notamment lorsqu’il est fortement dopé p. Le diamant est notamment adapté à la croissance de nitrures d’éléments III, et transparent aux rayonnements, notamment UV, obtenus par les diodes réalisées en ces matériaux. Diamond is in particular a material transparent over a wide range of wavelengths and capable of being conductive, especially when it is heavily p-doped. Diamond is particularly suitable for the growth of element III nitrides, and transparent to radiation, especially UV, obtained by diodes made of these materials.
En outre, le dopage p des nitrures d’éléments III et notamment de GAIN est difficile, et il est donc particulièrement intéressant d’utiliser le diamant dopé p comme couche fenêtre pour limiter l’utilisation de nitrures d’éléments III et notamment d’AIN dopés p et peu conducteurs. In addition, the p-doping of element III nitrides and in particular of GAIN is difficult, and it is therefore particularly advantageous to use p-doped diamond as a window layer to limit the use of element III nitrides and in particular of AIN p-doped and poorly conductive.
Les structures tridimensionnelles et notamment les nanofils de nitrures d’éléments III et notamment d’AIN permettent un dopage p plus efficace que des structures bidimensionnelles. The three-dimensional structures and in particular the nanowires of element III nitrides and in particular AIN allow more efficient p-doping than two-dimensional structures.
La coalescence et/ou l’injection de matériau de remplissage, suivie(s) d’un polissage, permettent d’obtenir des faces 150 planes et permettant une bonne fixation à la couche de réflexion 35. En particulier, l’injection de matériau de remplissage permet d’éviter d’endommager excessivement les structures tridimensionnelles lors du polissage. The coalescence and / or the injection of filling material, followed (s) by polishing, make it possible to obtain faces 150 that are flat and allow good attachment to the reflection layer 35. In particular, the injection of material filling prevents excessive damage to three-dimensional structures during polishing.
La portion métallique 35 du support 15 permet de refléter le rayonnement et donc d’augmenter le rendement de sortie du dispositif émetteur 10. En outre, cette couche 35 permet aussi une alimentation électrique aisée de la diode 20. Il est à noter que selon des modes de réalisation envisagés, le dispositif émetteur 10 comporte, en outre, un convertisseur (parfois appelé « phosphore ») configuré pour absorber tout ou partie du rayonnement et pour émettre en réponse un rayonnement présentant une longueur d’onde moyenne différente, notamment strictement plus longue, que la longueur d’onde moyenne du rayonnement émis. Le convertisseur est alors, par exemple, disposé en contact avec la couche fenêtre 25, la couche fenêtre 25 étant notamment interposée entre le convertisseur et la diode électroluminescente 20. The metallic portion 35 of the support 15 makes it possible to reflect the radiation and therefore to increase the output efficiency of the emitting device 10. In addition, this layer 35 also allows easy power supply of the diode 20. It should be noted that according to the embodiments envisaged, the emitting device 10 further comprises a converter (sometimes called a “phosphor”) configured to absorb all or part of the radiation and to emit in response a radiation having a length of. different mean wave, in particular strictly longer, than the mean wavelength of the emitted radiation. The converter is then, for example, placed in contact with the window layer 25, the window layer 25 being in particular interposed between the converter and the light-emitting diode 20.
Bien que le cas spécifique dans lequel le matériau de substrat est le diamant et le premier type de dopage est le dopage p soit décrit en détails ci-dessus, d’autres configurations sont envisageables, notamment des configurations dans lesquelles le premier type de dopage est le dopage n et le deuxième type de dopage est le dopage p. Although the specific case in which the substrate material is diamond and the first type of doping is p-doping is described in detail above, other configurations are conceivable, in particular configurations in which the first type of doping is. n doping and the second type of doping is p doping.
Par exemple, le premier type de dopage est le dopage n, le matériau de substrat est AIN, dopé n, et le deuxième matériau est, par exemple, AIGaN dopé p. De telles configurations comportent, par exemple, des diodes électroluminescentes 20 planaires, bien que des configurations dans lesquelles les diodes électroluminescentes 20 comportent des structures tridimensionnelles sont également envisageables. For example, the first type of doping is n doping, the substrate material is AIN, n doped, and the second material is, for example, AIGaN p doped. Such configurations include, for example, planar light emitting diodes 20, although configurations in which light emitting diodes 20 have three dimensional structures are also conceivable.
Lorsque le premier type de dopage est le dopage n, la couche bloqueuse d’électrons fait alors par exemple partie de la deuxième portion 50. When the first type of doping is n doping, the electron blocking layer is then for example part of the second portion 50.
A titre d’exemple, si le substrat est du diamant dopé p ou de GAIN dopé p, la première portion 40 est réalisée en un nitrure d’élément III présentant un dopage de type p, la deuxième portion 50 est réalisée en un matériau présentant un dopage de type n, la portion d’émission 45 étant interposée entre les portions 40 et 50 et présentant un dopage de type n ou p, ou encore étant non-intentionnellement dopée. By way of example, if the substrate is p-doped diamond or p-doped GAIN, the first portion 40 is made of an element III nitride exhibiting p-type doping, the second portion 50 is made of a material exhibiting n-type doping, the emission portion 45 being interposed between the portions 40 and 50 and exhibiting n-type or p-type doping, or else being unintentionally doped.
Lorsque le substrat est de GAIN dopé n, la première portion 40 est, par exemple, réalisée en un nitrure d’élément III présentant un dopage de type n, la deuxième portion 50 est réalisée en un matériau présentant un dopage de type p, la portion d’émission 45 étant interposée entre les portions 40 et 50 et présentant un dopage de type n ou p, ou encore étant non-intentionnellement dopée. When the substrate is of n-doped GAIN, the first portion 40 is, for example, made of an element III nitride exhibiting n-type doping, the second portion 50 is made of a material exhibiting p-type doping, the emission portion 45 being interposed between portions 40 and 50 and exhibiting n or p type doping, or else being unintentionally doped.

Claims

REVENDICATIONS
1. Procédé de fabrication d’un dispositif émetteur (10) comportant une diode électroluminescente (20) configurée pour émettre un rayonnement, la diode électroluminescente (20) comportant une première portion (40), une deuxième portion (50) et une portion d’émission (45), la première portion (40) étant réalisée en un premier matériau semi-conducteur présentant un premier type de dopage, la deuxième portion (50) étant réalisée en un deuxième matériau semi-conducteur présentant un deuxième type de dopage différent du premier type de dopage, la portion d’émission (45) étant interposée entre la première portion (40) et la deuxième portion (50), la portion d’émission (45) étant réalisée en un matériau d’émission semi-conducteur configuré pour émettre le rayonnement lorsque la diode électroluminescente (20) est traversée par un courant électrique, le procédé comportant des étapes de : fourniture (100) d’un substrat (70) réalisé au moins partiellement en un matériau de substrat semi-conducteur présentant le premier type de dopage, le matériau de substrat étant transparent au rayonnement, le substrat (70) présentant une première face (85) délimitant le substrat (70) selon une direction (N) normale à la première face (85), implantation (110), à travers la première face (85), d’un ensemble d’atomes apte à former une portion fragilisée dans le matériau de substrat, la portion fragilisée (90) s’étendant parallèlement à la première face (85), le substrat (70) comportant en outre une portion de surface (92) et une portion interne (95), la portion fragilisée (90) séparant la portion de surface (92) de la portion interne (95) selon la direction normale (N), 1. A method of manufacturing an emitting device (10) comprising a light emitting diode (20) configured to emit radiation, the light emitting diode (20) comprising a first portion (40), a second portion (50) and a portion of 'emission (45), the first portion (40) being made of a first semiconductor material having a first type of doping, the second portion (50) being made of a second semiconductor material having a second different type of doping of the first type of doping, the emission portion (45) being interposed between the first portion (40) and the second portion (50), the emission portion (45) being made of a semiconductor emission material configured to emit the radiation when an electric current passes through the light emitting diode (20), the method comprising the steps of: providing (100) a substrate (70) made at least partially of a semiconductor substrate material exhibiting the first type of doping, the substrate material being transparent to radiation, the substrate (70) having a first face (85) delimiting the substrate (70) in a direction (N) normal to the first face (85), implantation (110), through the first face (85), of a set of atoms capable of forming a weakened portion in the substrate material, the weakened portion (90) extending parallel to the first face (85), the substrate (70) further comprising a surface portion (92) and an internal portion (95), the weakened portion (90) separating the surface portion (92) from the internal portion (95) in the normal direction (N) ),
- formation (120), sur la première face (85), de la diode électroluminescente (20) par dépôt au moins du premier matériau, du matériau d’émission et du deuxième matériau, la première portion (40) étant interposée selon la direction normale (N) entre la portion d’émission (45) et la première face (85), la portion de surface (92) du substrat (70) étant solidaire de la première portion (40), la diode électroluminescente (20) étant délimitée selon la direction normale (N) par la première face (85) et par une face d’extrémité (150) de la deuxième portion (50), fixation (130) de la face d’extrémité (150) à une deuxième face (155) d’un support (15), la deuxième portion (50) étant interposée selon la direction normale (N) entre le support (15) et la portion d’émission (45), et - Formation (120), on the first face (85), of the light-emitting diode (20) by depositing at least the first material, the emission material and the second material, the first portion (40) being interposed in the direction normal (N) between the emission portion (45) and the first face (85), the surface portion (92) of the substrate (70) being integral with the first portion (40), the light emitting diode (20) being delimited in the normal direction (N) by the first face (85) and by an end face (150) of the second portion (50), fixing (130) of the end face (150) to a second face (155) of a support (15), the second portion (50) being interposed in the normal direction (N) between the support (15) and the emission portion (45), and
- rupture (140) de la portion fragilisée (90) pour séparer la portion de surface (92) du matériau de substrat de la portion interne (95) du matériau de substrat. - Breaking (140) of the weakened portion (90) to separate the surface portion (92) of the substrate material from the internal portion (95) of the substrate material.
2. Procédé selon la revendication 1 , dans lequel l’ensemble d’atomes implanté dans le substrat pour former une portion fragilisée comprend des atomes d’hydrogène, 2. The method of claim 1, wherein the set of atoms implanted in the substrate to form an embrittled portion comprises hydrogen atoms,
3. Procédé selon la revendication 1 ou 2, dans lequel le matériau de substrat est le diamant. 3. The method of claim 1 or 2, wherein the substrate material is diamond.
4. Procédé selon la revendication 1 ou 2, dans lequel le matériau de substrat est le nitrure d’aluminium. 4. The method of claim 1 or 2, wherein the substrate material is aluminum nitride.
5. Procédé selon l’une quelconque des revendications précédentes, dans lequel le rayonnement est un rayonnement ultra-violet, notamment un rayonnement présentant une longueur d’onde moyenne comprise entre 250 nanomètres et 280 nanomètres. 5. Method according to any one of the preceding claims, in which the radiation is ultra-violet radiation, in particular radiation having an average wavelength of between 250 nanometers and 280 nanometers.
6. Procédé selon l’une quelconque des revendications précédentes, dans lequel au moins une des propriétés suivantes est vérifiée : 6. Method according to any one of the preceding claims, in which at least one of the following properties is verified:
- le premier matériau, le deuxième matériau et le troisième matériau sont des nitrures d’élément III, et/ou - the first material, the second material and the third material are element III nitrides, and / or
- le matériau de substrat est monocristallin. - the substrate material is monocrystalline.
7. Procédé selon l’une quelconque des revendications précédentes, dans lequel le premier type de dopage est le dopage de type p. 7. A method according to any preceding claim, wherein the first type of doping is p-type doping.
8. Procédé selon l’une quelconque des revendications précédentes, comportant, en outre, une étape de fourniture d’un circuit d’alimentation de la diode électroluminescente (20) et une étape de connexion de la portion de surface (92) au circuit d’alimentation. 8. A method according to any preceding claim, further comprising a step of providing a power supply circuit of the light emitting diode (20) and a step of connecting the surface portion (92) to the circuit. power supply.
9. Procédé selon l’une quelconque des revendications précédentes, dans lequel la diode électroluminescente (20) comporte un ensemble de nanofils s’étendant chacun selon la direction normale (N), chaque nanofil comportant une base (55) réalisée en le premier matériau, une portion intermédiaire (60) réalisée en le matériau d’émission et une portion d’extrémité (65) réalisée en le deuxième matériau, la première portion (40) étant formée par la réunion des bases (55) des nanofils, la portion d’émission (45) étant formée par la réunion des portions intermédiaires (60), la deuxième portion (50) étant formée par la réunion des portions d’extrémité (65). 9. Method according to any one of the preceding claims, in which the light-emitting diode (20) comprises a set of nanowires each extending in the normal direction (N), each nanowire comprising a base (55) made of the first material. , an intermediate portion (60) made of the emission material and an end portion (65) made of the second material, the first portion (40) being formed by the meeting of the bases (55) of the nanowires, the portion emission (45) being formed by the meeting of the intermediate portions (60), the second portion (50) being formed by the meeting of the end portions (65).
10. Procédé selon la revendication 9, comportant l’une des étapes suivantes :10. The method of claim 9, comprising one of the following steps:
- une étape de coalescence des portions d’extrémité (65) des nanofils pour former la face d’extrémité (150), et/ou - une étape d’injection d’un matériau de remplissage transparent au rayonnement entre les nanofils antérieurement à l’étape de fixation (130). - a step of coalescing the end portions (65) of the nanowires to form the end face (150), and / or - a step of injecting a filler material transparent to radiation between the nanowires prior to the 'fixing step (130).
11. Procédé selon l’une quelconque des revendications précédentes, dans lequel le support (15) comporte une portion métallique (35) délimitée par la deuxième face (155), la portion métallique (35) étant fixée à la diode électroluminescente (20) au cours de l’étape de fixation (140). 11. Method according to any one of the preceding claims, wherein the support (15) comprises a metal portion (35) delimited by the second face (155), the metal portion (35) being fixed to the light-emitting diode (20). during the fixing step (140).
12. Dispositif émetteur (10) susceptible d’être obtenu par un procédé selon l’une quelconque des revendications précédentes. 12. Transmitter device (10) obtainable by a method according to any one of the preceding claims.
EP21717112.3A 2020-04-15 2021-04-13 Method for manufacturing a device for emitting radiation Pending EP4136681A1 (en)

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FR2003779A FR3109469B1 (en) 2020-04-15 2020-04-15 Method of manufacturing a radiation emitting device
PCT/EP2021/059580 WO2021209460A1 (en) 2020-04-15 2021-04-13 Method for manufacturing a device for emitting radiation

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