JP5405039B2 - Current confinement type light emitting device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a current-confined light-emitting element capable of improving internal quantum efficiency and light extraction efficiency over a large current, and having both light emission intensity and reliability with high light output performance, and a method for manufacturing the same.

  In recent years, with the diversification of uses of LED (semiconductor light-emitting elements) such as application to automobile headlamps, brake lamps, and traffic lights, use of LEDs with high output and large current is required.

  In general, in a LED, a semiconductor layer including a light emitting portion is stacked on a substrate, and a first electrode layer and a second electrode layer are provided on the lower surface and the upper surface of the semiconductor layer stacked substrate, respectively, and a p-type semiconductor is interposed therebetween. It has a structure including a first conductive semiconductor layer such as a layer, a second conductive semiconductor layer such as an n-type semiconductor layer, and an active layer (light emitting portion) between these semiconductor layers.

  When current is injected into the LED, photons generated in the active layer travel in all directions, but those that reach the first electrode layer are absorbed and reflected by the electrode material of the first electrode layer, and light is emitted to the outside of the LED. Is not output as. In particular, in a thin-film semiconductor layer laminated by the MOCVD (Metal Organic Chemical Deposition) method or the like, most of the light generated in the active layer immediately below the first electrode layer is absorbed and reflected by the first electrode layer. There has been a problem that the light extraction efficiency is greatly reduced.

  Therefore, the output reduction due to light shielding at the first electrode layer is improved by, for example, introducing a larger amount of current to the active layer that is not positioned immediately below the first electrode layer. The more the active layer that is the photon generation position is located farther from the position immediately below the first electrode layer, the less the influence of the generated light that is blocked by the first electrode layer.

  The current confinement region, which concentrates the current only in a specific region of the active layer, increases the probability of carrier recombination by concentrating the electrons and holes injected there, so that the internal quantum efficiency can be improved. it can.

  For example, in Patent Document 1, a GaAs substrate, a light emitting unit formed by laminating a first conductivity type InGaAlP layer and a second conductivity type InGaAlP layer on the substrate, and a part of the light emitting unit are formed. A first conductive layer having an energy gap larger than that of the substrate and smaller than that of the first conductive type layer between the first conductive type layer of the light emitting unit and the substrate. A technique of selectively forming a middle energy gap layer of a mold and directly contacting a first conductive type InGaAlP layer and a substrate at least at a part under the electrode, wherein an intermediate energy gap is formed at a junction with the substrate. Since a large amount of current flows through the layers, high output is achieved by improving internal quantum efficiency due to current confinement and improving efficiency of extracting generated light.

  However, in the semiconductor layer described in Patent Document 1, since the GaAs substrate is used as the supporting substrate, the semiconductor layer is thin, the lateral current spread is poor, and the active layer near the upper electrode outer periphery vertically often emits light strongly. There is room for improvement in light extraction efficiency.

  Further, in order to efficiently extract light directed from the active layer toward the substrate, there is a wafer bonding technique in which a semiconductor layer laminated substrate is bonded to another substrate directly or via a bonding layer. Discloses a technique in which a light-emitting element is formed by attaching another substrate to a semiconductor layer laminated substrate through a bonding layer including a reflective film and then removing the substrate used for the semiconductor layer lamination. Of the light generated in the active layer inside, the light directed toward the junction is reflected by the reflective film having a high reflectivity and extracted from the surface of the semiconductor layer facing the junction, thereby absorbing light at the substrate. Prevents and improves output.

  Furthermore, in the structure described in Patent Document 2, an insulating layer is formed at the junction so as to be in contact with the semiconductor layer, and an opening of the insulating layer is formed only in a part of the region other than vertically below the upper surface electrode. It is disclosed that an output improvement effect is obtained by current confinement.

However, in the semiconductor layer described in Patent Document 2, when a constriction structure is formed with an insulating layer having a small opening, when a large current is applied, the amount of heat generated locally at the portion where the current is concentrated increases and the output decreases. In addition, the reliability as a light emitting element may be adversely affected.
Japanese Patent No. 2766311 JP 2007-221029 A

  Accordingly, an object of the present invention is to obtain a high-power light-emitting element, and at a large current, the concentration of the current density can be relaxed to reduce a decrease in output, and the current confinement also has reliability as a light-emitting element. It is providing a type light emitting element.

In order to achieve the above object, the gist of the present invention is as follows.
(1) On the upper surface side of the support substrate, a metal laminate composed of two conductive layers made of different conductive materials, a first conductive type semiconductor layer, an active layer, a second conductive type semiconductor layer, and a first electrode layer, In the current confinement type light emitting device having the second electrode layer on the lower surface side of the support substrate, the metal laminate includes a first conductive layer having a convex portion in contact with the first conductive type semiconductor layer, and the first conductive layer. And a second conductive layer having a second surface located on a portion of the first surface other than the convex portion and in contact with the first conductive type semiconductor layer, wherein the first conductive layer includes the first conductive layer contact resistance to the first conductivity type semiconductor layer is lower than that of the second conductive layer, and the convex portion, Ri Na and disposed at a position shifted from the vertical lower portion of the arrangement position of the first electrode layer, More current density than the first conductive layer at the interface between the second conductive layer and the first conductive type semiconductor layer. A current confinement-type light-emitting device characterized Rukoto low current flows.
(2) The current confinement type light emitting device according to (1), wherein the first conductive layer is a metal layer made of Au or Ag, or an alloy layer containing Au or Ag.
(3) The current confined light-emitting element according to (1), wherein the second conductive layer is a metal layer made of Al or Ag, or an alloy layer containing Al and / or Ag.
(4) A step of sequentially forming a second conductive type semiconductor layer, an active layer and a first conductive type semiconductor layer above the second conductive type growth substrate, and a second conductive type above the first conductive type semiconductor layer. A step of forming a layer; a step of forming a recess in the second conductive layer; and a surface portion of the first conductivity type semiconductor layer exposed from the recess and the first conductive layer above the second conductive layer. A step of performing a heat treatment for reducing contact resistance between the first and second conductive layers and the first conductive type semiconductor layer, and after the heat treatment , a support is provided above the first conductive layer. A step of bonding the substrate, a step of removing the second conductivity type growth substrate, and a step of forming a first electrode layer on the second conductivity type semiconductor layer and a second electrode layer on the lower surface side of the support substrate. When the equipped, and wherein Rukoto obtain a current confinement-type light-emitting device according to (1) Method for producing a current confinement-type light-emitting element that.
(5) The method for manufacturing a current confining light-emitting element according to (4), wherein the supporting substrate bonding step includes bonding the supporting substrate through a metal bonding layer.

  Here, the “contact resistance” is not only a narrowly-defined resistance component showing ohmic characteristics at the contact portion between the conductive layer and the first conductivity type semiconductor layer, but also from a voltage drop at the contact portion and the portion including the periphery thereof. The estimated resistance, for example, a characteristic defined by the impedance of the entire equivalent circuit including the contact portion and its periphery.

In the semiconductor light emitting device of the present invention, the metal laminate is provided on the first conductive layer having a convex portion that contacts the first conductivity type semiconductor layer, and on the first surface portion of the first conductive layer other than the convex portion. And a second conductive layer having a second surface in contact with the first conductive type semiconductor layer, the first conductive layer having a contact resistance to the first conductive type semiconductor layer, It is lower than the conductive layer, and the convex portion is disposed at a position shifted from the vertically lower position of the position where the first electrode layer is disposed , and the second conductive layer and the first conductive semiconductor layer the interface, by Rukoto the current density than the first conductive layer is low current flows, it is possible to improve the light extraction efficiency over a large current, it is possible to achieve both the emission intensity and reliability of high light output performance .

The method for manufacturing a semiconductor light emitting device of the present invention includes a step of forming a recess in the second conductive layer, a surface portion of the first conductivity type semiconductor layer exposed from the recess, and above the second conductive layer. A current confinement type light emitting device comprising: a step of forming a first conductive layer; and a step of performing a heat treatment for reducing contact resistance between the first and second conductive layers and the first conductive type semiconductor layer. The light output performance can be improved.

Hereinafter, embodiments of the current confined light emitting device of the present invention will be described in detail with reference to the drawings.
FIG. 1 schematically shows an embodiment of a current confinement type light emitting device according to the present invention with respect to a partial cross-sectional structure of a semiconductor light emitting device.

  A semiconductor light emitting device 1 shown in FIG. 1 has a metal laminate 3, a first conductive semiconductor layer 4, an active layer 5, a second conductive semiconductor layer 6, and a first electrode layer 7 on the upper surface side of a support substrate 2. In addition, this is a so-called current confining type light emitting element having the second electrode layer 8 on the lower surface side of the support substrate 2.

For example, suitable materials constituting the support substrate 2 include, for example, Si materials, GaAs materials, GaP materials, SiC materials, other semiconductor substrate materials, metal substrates such as Cu and Al, and the like. The type semiconductor layer 4 is an n-type semiconductor layer represented by Al _a Ga _(1-a) As (0 ≦ a ≦ 1), and the active layer 5 is In _b Ga _(1-b) As (0 <b ≦ 1) and Al _c Ga _(1-c) As (0 ≦ c ≦ 1), and the second conductivity type semiconductor layer 6 is made of Al _d Ga _(1-d) As (0 ≦ d ≦ 1). The p-type semiconductor layer represented by this is mentioned.
The first conductivity type semiconductor layer 4 is made of an (Al _f Ga _(1-f) ) _0.5 In _0.5 P layer (0 ≦ f ≦ 1), and the active layer 5 is made of In _g Ga _{(1-g )} Multiple quantum well comprising P layer (0 <g ≦ 1) and Al _h Ga _i In _(1-hi) P layer (0 ≦ h ≦ 1, 0 ≦ i ≦ 1, and 0 ≦ h + i ≦ 1) The layer and the second conductivity type semiconductor layer 6 may be (Al _j Ga _(1-j) ) _0.5 In _0.5 P layer (0 ≦ j ≦ 1).
The first electrode layer 7 needs to be joined at a part of the second conductivity type semiconductor layer 6 and to form an ohmic junction with a low contact resistance at the interface. When the first conductivity type semiconductor layer 4 is AlGaAs or AlGaInP, alloys such as Au—Zn and Au—Sb are preferable in addition to Au and Ag.
Although the second electrode layer 8 is not insulated, it needs to have a higher contact resistance with the semiconductor layer than the first electrode layer 7 and has good adhesion between the semiconductor layer and the first metal layer 7. It is a requirement. A metal that reflects light from the light emitting layer is also preferable in terms of improving the light emission efficiency. A metal having a high contact resistance with the semiconductor layer as compared with the first electrode layer is preferably a metal having a Schottky connection with the semiconductor layer. Considering these comprehensively, Al, Ag, or an alloy containing these components can be mentioned, but Al is most preferable.

  The support substrate 2 is preferably 100 to 400 μm thick, the first conductive semiconductor layer 4 is preferably 1 to 2 μm thick, and the second conductive semiconductor layer 6 is preferably 5 to 5 μm. It has a thickness of 10 μm. This is because by reducing the thickness of the first conductive type semiconductor layer 4, the current confinement effect in the active layer 5 is reduced by lateral current diffusion in the same layer as compared with the case of increasing the thickness.

The semiconductor light emitting element 1 preferably includes a metal bonding layer 9 having conductivity between the support substrate 2 and the metal laminate 3. By providing the metal bonding layer 9, the support substrate 2 and the metal laminate 3 can be bonded by thermocompression bonding.
As a suitable material which comprises the metal joining layer 9, Au, Cu, etc. are mentioned, for example, Preferably it has a thickness of 1-2 micrometers.

  The main structural features of the light-emitting element 1 according to the present invention are that the metal laminate 3 includes a first conductive layer 10 having a convex portion 10 a that contacts the first conductive semiconductor layer 4, and the first conductive layer 10. The second conductive layer 11 is located on a portion of the first surface 10b other than the convex portion 10a and has the second surface 11b in contact with the first conductive type semiconductor layer 4, and the first conductive layer 10 The contact resistance with respect to the first conductive type semiconductor layer 4 is lower than that of the second conductive layer 11, and the convex portion 10a is disposed at a position shifted from the vertically lower position of the position where the first electrode layer 7 is disposed. That is.

  By adopting such a configuration, the current density to the light emitting region S in the active layer 5 (light emitting portion) is increased, a light output with a uniform light distribution in the light emitting region S can be obtained, and a high current density can be obtained. However, it is possible to prevent a decrease in output due to local heat generation and improve reliability.

  That is, the metal laminate 3 is positioned on the first conductive layer 10 having the convex portion 10a that is in contact with the first conductivity type semiconductor layer 4 and the first upper surface 10b of the first conductive layer 10 other than the convex portion 10a. And the second conductive layer 11 having the second upper surface 11b in contact with the first conductivity type semiconductor layer 4 to reduce the opening at a position away from vertically below the upper electrode of the active layer 5, A region having a high current density will be formed locally, and a significant improvement in internal quantum efficiency and light extraction efficiency is expected. The current density to the light emitting region S is increased, and the light emission intensity can be improved.

  Further, the first conductive layer 10 has a lower contact resistance with respect to the first conductive type semiconductor layer 4 than the second conductive layer 11, so that the interface between the first conductive layer 10 and the first conductive type semiconductor layer 4. As a result, a large amount of current flows through the first conductive layer 10 to increase the constriction effect.

  The light extraction efficiency can be improved over a high current density because the current confining means is not an insulator or a semiconductor confining layer of a different conductivity type but a second conductive layer having a high resistance portion such as a Schottky. 11 is used. Although no current flows through the insulator or the constricted layer, the current flows in the second conductive layer 11 although the current density is lower than that of the first conductive layer 10, so that the convex portion 10 a of the first conductive layer 10 is formed. As a maximum, the second conductive layer 11 also has a current density distribution that spreads out to the bottom, and has the effect of improving the output due to constriction, and also prevents the output and reliability from being reduced due to current concentration at a large current.

Current-voltage (IV) between each conductive layer and semiconductor layer when Au is used as the first conductive layer 10, aluminum Al is used as the second conductive layer 11, and p-type AlGaAs is used as the first conductive type semiconductor layer 4. A comparative diagram of the curves is shown in FIG.
The first conductivity type semiconductor layer 4 was C-doped p-type Al _0.3 Ga _0.7 As, the thickness was 5 μm, and the carrier concentration was 1 × 10 ¹⁸ (cm ⁻³ ). Au or Al is vapor-deposited on this p-type AlGaAs, and dots having a diameter of 110 μm and a thickness of 100 nm are arranged at a center distance of 275 μm. After heat treatment at 380 ° C., I− V measurement was performed.

  From FIG. 2, the IV of Au with respect to p-type AlGaAs is linear, and the total resistance between the two electrodes is required to be about 50Ω (ohmic contact). The IV of Al with respect to p-type AlGaAs is non-linear, a voltage drop at the contact portion is confirmed, and the total resistance between the two electrodes when approximating the range of 0 to 1 V is approximated to about 400Ω. it can. (Schottky contact).

  When both the first conductive layer 10 and the second conductive layer 11 form an ohmic contact with the first conductive type semiconductor layer 4, the contact portion between the conductive layer and the semiconductor layer required by a TLM (Transmission Line Model) method or the like The resistance components in a narrow sense can be compared, and the combination of the conductive layers can be determined by the magnitude of the resistance components.

When one or both of the first conductive layer 10 and the second conductive layer 11 form a Schottky contact, a broad resistance component can be obtained from measurement of AC conductivity using a high-frequency power source. The combination of the conductive layers can be determined depending on the size.
It is possible to distinguish between Schottky and ohmic by IV measurement as shown in FIG. 2, and it is possible to compare the magnitude of the contact resistance qualitatively.

  And the convex part 10a of the 1st conductive layer 10 is located under the 1st electrode layer 7 of the active layer 5 by arrange | positioning in the position shifted from the position directly under arrangement | positioning of the 1st electrode layer 7. FIG. Since a large amount of current is concentrated in the non-existing portion, the light in the light emitting region S is output from the light emitting region S without being interrupted by the first electrode layer 7, so that the light extraction efficiency can be improved. .

FIG. 3 schematically shows a top view of the semiconductor light emitting device of the present invention.
In such a current confinement type light emitting device, preferably, the first electrode layer 7 is provided in a ring shape on the outer periphery of the upper surface of the second conductive semiconductor layer 6, and the convex portion 10 a of the first conductive layer 10 It is provided corresponding to the center position C of the light emitting region S surrounded by the electrode layer 7. Thus, by forming the convex portion 10a of the first conductive layer 10 at a position away from the position where the first electrode layer 7 is provided, high internal quantum efficiency and light extraction efficiency can be obtained. Further, by arranging the distance between the position of the first electrode layer 7 and the position of the convex portion 10a of the first conductive layer 10 to be uniform within the chip, all the 15 light emitting regions S within the chip are evenly distributed. With a high intensity, it is possible to emit light in a centrally symmetrical manner with no light emission in each light emitting region. In FIG. 3, the shape of the convex portion 10 a is circular, but may be rectangular, and can be changed according to the shape of the first electrode layer 7.

  The first conductive layer 10 is preferably a metal layer made of Au or Ag, or an alloy layer containing Au or Ag. The first conductive layer 10 forms an ohmic contact with a low contact resistance with the first conductive type semiconductor layer 4, and By allowing more current to flow than the two conductive layers 11, the internal quantum efficiency can be improved.

  The second conductive layer 11 is preferably a metal layer made of Al or Ag, or an alloy layer containing Al and / or Ag, and forms a Schottky contact with high contact resistance with the first conductive type semiconductor layer 4. At the same time, the light extraction effect can be improved by the reflection effect.

In this invention, it is preferable that the convex part 10a of the 1st conductive layer 10 exists in the position away from the direct lower part of the 1st electrode layer 7 arrangement | positioning position more than the total thickness of the semiconductor layers 4-6. That is, the convex portion 10a is not arranged in the vertically downward direction of the first electrode layer 7, and the end portion of the first electrode layer and the end portion of the convex portion 10a are arranged with respect to the perpendicular of the end portion of the first electrode layer 7. It is preferable that the connecting straight line is long. More preferably, the position of the convex portion 10a is located farthest from the position of the first electrode layer 7. This is because the center of the light emitting region in the active layer 5 (light emitting portion) is moved away from the first electrode layer, and the influence of light shielding on the first electrode layer 7 is further reduced.
Regarding the protrusion top surface 10a ₁ of the first conductive layer 10, in view of the aspect ratio, the minimum size is limited. Although depending on the thickness of the second conductive layer 11, the top surface 10 a _{1 of the} convex portion is preferably 10 μm or more in diameter if it is circular.

Next, an embodiment of a method for manufacturing a current confined light emitting device of the present invention will be described with reference to the drawings.
4A to 4F show the main steps in the method for manufacturing a semiconductor light emitting device according to the present invention.

  As shown in FIG. 4A, the manufacturing method of the current confinement type light emitting device of the present invention has a second conductive type semiconductor layer 6, an active layer 5 and a first conductive type above the second conductive type growth substrate 12. The semiconductor layer 4 is formed sequentially. These layers 4 to 6 are sequentially formed by one epitaxial growth by a thin layer growth method such as MOCVD (metal organic chemical vapor deposition).

  Next, as shown in FIG. 4B, the second conductive layer 11 is formed above the first conductive type semiconductor layer 4 by, for example, electron beam co-evaporation or resistance heating.

Thereafter, as shown in FIG. 4C, a part of the second conductive layer 11, that is, the vicinity of the center in the figure, is removed by, for example, wet etching using an NaOH etching solution or dry etching using a predetermined gas. 11a is formed.
Thereafter, as shown in FIG. 4D, the first conductive layer 10 is formed on the surface portion of the first conductive type semiconductor layer 4 exposed from the recess 11a and above the second conductive layer 11, and the second conductive layer is formed. 11 and a heat treatment for reducing the contact resistance between the first conductivity type semiconductor layer 4.

  Then, as shown in FIG. 4E, the support substrate 2 is bonded above the first conductive layer 10.

  Thereafter, as shown in FIG. 4F, the second conductivity type growth substrate 12 is removed by, for example, a wet etching method using a predetermined etching solution.

  In the manufacturing method of the present invention, the metal laminate 3, the first conductive semiconductor layer 4, the active layer 5 and the second conductive semiconductor layer 6 are formed on the upper surface side of the support substrate 2 constituting the semiconductor light emitting device 1. The current confinement type light emitting device of the present invention can be manufactured by performing epitaxial growth once.

  When joining the support substrate 2, it is preferable to join the support substrate 2 through the metal joining layer 9, as shown in FIG.4 (e). The metal bonding layer 9 includes a bonding metal material, for example, a bonding layer 9a made of Au, Cu, or various solder materials in advance on the upper surface of the first conductive layer 10, and a bonding metal material in advance on the upper surface of the support substrate 2. For example, it is preferable to form a bonding layer 9b of Au, Cu or various solder materials by vapor deposition, and bond them by thermocompression bonding. By bonding through these metals, it is possible to bond the substrates at a low temperature, and it is possible to bond without deteriorating the characteristics and structure of the semiconductor layer.

  After removing the second conductivity type growth substrate 12, the first electrode layer 7 is formed on the second conductivity type semiconductor layer 6, the second electrode layer 8 is formed on the lower surface side of the support substrate 2, and dicing is performed. It is preferable to form the semiconductor light emitting device 1 as shown in 4 (f).

  The above description is merely an example of the embodiment of the present invention, and various modifications can be made within the scope of the claims.

(Example)
Next, on the upper surface side of the second conductivity type growth substrate 12 (GaAs, thickness: 350 μm), the second conductivity type semiconductor layer 6 (Al _0.4 Ga _0.6 As layer, thickness: 5 μm), active layer 5 (InGaAs / AlGaAs multiple quantum well structure, thickness: 50 nm) and first conductive semiconductor layer 4 (Al _0.4 Ga _0.6 As layer, thickness: 2 μm) were sequentially formed by MOCVD.

  Thereafter, a second conductive layer 11 (Al, thickness: 100 nm) was deposited on the first conductive type semiconductor layer 4 by an electron beam deposition method.

The second conductive layer 11 was wet-etched using a NaOH etching solution by a photolithography process to form a recess 11a. Thereafter, an Au first conductive layer 10 (thickness: 500 nm) was deposited by resistance heating on the surface portion of the first conductive type semiconductor layer 4 exposed from the recess 11a and above the second conductive layer 11. The area of the convex top surface 10a ₁ of the first conductive layer 10 was 4700 μm ^2. Thereafter, heat treatment for making ohmic contact was performed, and an Au bonding layer 9 a (thickness: 0) was formed thereon by electron beam evaporation. 0.5-1 μm).

  On the other hand, on the support substrate 2 (GaAs, thickness: 350 μm), an ohmic contact was formed, and then an Au bonding layer 9b (thickness: 0.5 to 1 μm) was formed thereon by electron beam evaporation.

  Then, both the bonding layer 9a and the bonding layer 9b were bonded to each other by thermocompression bonding at 350 ° C. for 30 minutes.

  Next, wet etching is performed by swinging the structure configured as described above in a solution of ammonia water: hydrogen peroxide water: water = 1: 12: 18 (volume ratio) at room temperature for 2 hours. The second conductivity type growth substrate 12 was removed.

Then, the 2nd electrode layer 8 (thickness: 0.5-1 micrometer) which consists of AuZn / Au was vapor-deposited on the support substrate 2 by the boat heating type vapor deposition method. On the second conductivity type semiconductor layer 6, an AuGe / Ni / Au layer (thickness: 0.5 to 1 μm) was deposited by boat heating vapor deposition to form a first electrode layer 7.
Then, an upper surface pad is formed on the Ti / Au layer above the first electrode layer 7 by resistance heating. After the photolithography process, etching is performed with a mixed solution of phosphoric acid and hydrogen peroxide solution, and after forming a mesa, a dicer is used. Then, a square chip having a structure of 540 μm square as shown in FIG. 3 was manufactured.

The semiconductor light-emitting element 1 has a structure as shown in FIG. 3, and the dimensions of the light-emitting region S are a square having a side length s of 90 μm, a convex portion 10a having a diameter d of 20 μm, and a convex portion top surface 10a ₁ . The area is 4700 μm ² , and the existence ratio of the convex top surface 10a ₁ with respect to the chip area is about 1.6%.

(Comparative example)
The comparative example has substantially the same structure as the example, but as shown in FIG. 5, an insulating layer 32 (thickness 200 nm) made of SiN is provided between the second conductive layer 31 and the first conductive type semiconductor layer 24. Has been added to. A semiconductor light emitting device 21 was obtained by the same method as in the example except that the insulating layer 32 was disposed in the same position and in the same shape as the second conductive layer. The second conductive layer 31 was disposed in order to make the effect of reflecting the light from the active layer 25 equivalent to that of the example.

  Table 1 shows the results of measuring the output when a current was passed through the semiconductor light emitting devices of the above examples and comparative examples.

  As shown in Table 1, the light output was significantly improved in the example at a current of 50 mA or more as compared with the comparative example.

In the semiconductor light emitting devices of the above examples and comparative examples, the light emission profiles of the center position of the convex portion (point C) and the point on the inner side in the 5 μm width direction from the first electrode layer (point E) when current is passed are Near Field Pattern. The measurement was performed with the measuring device focused on the top surface of the chip and the center line of the chip passing through the center of the convex portion. The measurement results of the ratio of the emission intensity at point E to the emission intensity at point C are shown in Table 2 and FIGS.
The small current region was 1 to 20 mA, the medium current region was 40 to 60 mA, and the large current region was 80 to 120 mA.

  From the results shown in Table 2 and FIGS. 6 and 7, the embodiment observes a wide emission intensity (current) in the small to medium current region up to 50 mA and the center position in the large current region of 100 mA, compared to the comparative example. In the vicinity, no luminescence saturation was observed. That is, in the comparative example, when the current is increased, the emission intensity at the center C decreases due to heat generation due to current concentration at the center position, whereas in the embodiment, the emission intensity at the center position C as in the comparative example decreases. Saturation was not observed, and further increase in output at high current was confirmed due to relaxation of current concentration.

  In the semiconductor light emitting device of the present invention, the metal laminate is positioned on the first conductive layer having a convex portion that contacts the first conductive type semiconductor layer, and on the first upper surface portion of the first conductive layer other than the convex portion. And a second conductive layer having a second upper surface in contact with the first conductivity type semiconductor layer, and the first metal layer has a contact resistance with respect to the first conductivity type semiconductor layer, and the second conductivity layer. It is lower than the layer and the convex portion is disposed at a position immediately below the first electrode layer, so that the light output performance can be improved over a large current and the reliability can be improved. A semiconductor light-emitting element that can be provided can be provided.

  The method for manufacturing a semiconductor light emitting device of the present invention includes a step of forming a recess in the second conductive layer, a surface portion of the first conductivity type semiconductor layer exposed from the recess, and above the second conductive layer. Semiconductor light emission capable of improving the light output performance of the current confined light emitting device by providing a step of forming the first conductive layer and a step of forming the first conductive layer above the second conductive layer An element manufacturing method can be provided.

An embodiment of a current confinement type light emitting device according to the present invention is schematically shown with respect to a partial cross-sectional structure of a semiconductor light emitting device. Comparison diagram of current-voltage (IV) curves of each conductive layer and semiconductor layer when Au is used as the first conductive layer, Al is used as the second conductive layer, and p-type AlGaAs is used as the first conductive type semiconductor layer. Is shown. 1 is a schematic top view of a semiconductor light emitting device of the present invention. (A)-(f) is a conceptual diagram of the main processes in the manufacturing method of the semiconductor light-emitting device according to this invention. 1 schematically shows a partial cross-sectional structure of a current confinement light emitting element of a comparative example. The result of having measured the light emission profile by the Example is shown. The light emission profile measured by the Example is shown typically.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,21 Semiconductor light-emitting device 2,22 Support substrate 3 Metal laminated body 4,24 1st conductivity type semiconductor layer 5,25 Active layer 6,26 2nd conductivity type semiconductor layer 7,27 1st electrode layer 8,28 2nd Electrode layer 9, 29 Metal bonding layer 9a, 9b Bonding layer 10, 30 First conductive layer 10a Protruding portion 10b First surface 11, 31 Second conductive layer 11a Recessed portion 11b Second surface 12 Second conductive type growth substrate 32 Insulating layer

Claims (5)

The support substrate has a metal laminate composed of two conductive layers made of different conductive materials, a first conductivity type semiconductor layer, an active layer, a second conductivity type semiconductor layer, and a first electrode layer on the upper surface side of the support substrate, In the current confined light emitting device having the second electrode layer on the lower surface side of
The metal laminate is
A first conductive layer having a convex portion in contact with the first conductive semiconductor layer;
A second conductive layer having a second surface located on a portion of the first surface of the first conductive layer other than the convex portion and in contact with the first conductive type semiconductor layer;
The first conductive layer includes
The contact resistance with respect to the first conductive type semiconductor layer is lower than that of the second conductive layer, and the convex portion is disposed at a position shifted from the vertically lower position of the position at which the first electrode layer is disposed. The
Wherein the interface between the first conductive type semiconductor layer and the second conductive layer, the current confinement-type light-emitting element current density than the first conductive layer and said Rukoto low current flows.   The current confinement type light emitting device according to claim 1, wherein the first conductive layer is a metal layer made of Au or Ag, or an alloy layer containing Au or Ag.   2. The current confined light emitting device according to claim 1, wherein the second conductive layer is a metal layer made of Al or Ag, or an alloy layer containing Al and / or Ag. Forming a second conductive type semiconductor layer, an active layer and a first conductive type semiconductor layer sequentially on the second conductive type growth substrate;
Forming a second conductive layer above the first conductive semiconductor layer;
Forming a recess in the second conductive layer;
Forming a first conductive layer above the surface portion of the first conductive type semiconductor layer exposed from the recess and the second conductive layer;
Performing a heat treatment for reducing contact resistance between the first and second conductive layers and the first conductive semiconductor layer;
Bonding the support substrate above the first conductive layer after the heat treatment;
Removing the second conductivity type growth substrate ;
Forming a first electrode layer on the second conductivity type semiconductor layer and forming a second electrode layer on the lower surface side of the support substrate;
The comprising manufacturing method of the current confinement-type light-emitting device characterized Rukoto obtain a current confinement-type light emitting device according to claim 1.   The method of manufacturing a current confinement light-emitting element according to claim 4, wherein the supporting substrate bonding step includes bonding the supporting substrate through a metal bonding layer.

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