JP2022129162A - Semiconductor device and method for manufacturing semiconductor device - Google Patents

Abstract

A semiconductor device with reduced crosstalk is provided. A substrate, a plurality of first electrodes spaced apart from each other on the substrate, a first portion disposed on the plurality of first electrodes and a space on the space. and a photoelectric conversion layer containing a second portion, wherein the content of oxygen per unit volume in the second portion is based on the molar amount of oxygen per unit volume in the first portion higher than content. [Selection drawing] Fig. 4

Description

The present invention relates to a semiconductor device and a method for manufacturing a semiconductor device.

Patent Document 1 discloses a photoelectric conversion device using a photoelectric conversion layer. In the photoelectric conversion device described in Patent Document 1, an insulating partition is provided between the first region and the second region of the photoelectric conversion layer. This reduces crosstalk between the photodiodes corresponding to the first region and the photodiodes corresponding to the second region.

Further, Patent Document 2 discloses a photoelectric conversion device having another structure using a photoelectric conversion layer. In the photoelectric conversion device described in Patent Document 2, the photoelectric conversion layer between the plurality of photoelectric conversion elements is physically separated by patterning or the like. This reduces crosstalk between the plurality of photoelectric conversion elements.

JP-A-2015-73070 JP-A-2008-53252

In semiconductor devices using a photoelectric conversion layer as described in Patent Documents 1 and 2, reduction of crosstalk between elements has been studied as described above. However, there are cases where it is difficult to apply the methods of Patent Documents 1 and 2, and there are cases where crosstalk reduction is required by methods other than these methods.

An object of the present invention is to provide a semiconductor device with reduced crosstalk and a method of manufacturing the semiconductor device.

According to one aspect of the present invention, a substrate, a plurality of first electrodes spaced apart from each other on the substrate, and a first portion and the space disposed on the plurality of first electrodes and a photoelectric conversion layer including a second portion disposed on the second portion, wherein the content of oxygen per unit volume in the second portion on a molar basis is oxygen per unit volume in the first portion is higher than the molar content of the semiconductor device.

According to another aspect of the present invention, the steps of: preparing a substrate; forming a plurality of first electrodes spaced apart from each other on the substrate; a step of forming a photoelectric conversion layer including a first portion arranged above and a second portion arranged above the gap; and a step of irradiating the photoelectric conversion layer with light in an atmosphere containing oxygen. , wherein the second portion is irradiated with a larger amount of light than the first portion.

According to the present invention, a semiconductor device with reduced crosstalk and a method for manufacturing the semiconductor device are provided.

1 is a block diagram showing a schematic configuration of a photodetector according to a first embodiment; FIG. 4 is a circuit diagram showing an example of a pixel according to the first embodiment; FIG. 4 is a circuit diagram showing another example of a pixel according to the first embodiment; FIG. 1 is a schematic diagram of a photodetector according to a first embodiment; FIG. It is a cross-sectional schematic diagram explaining the effect of the photodetector based on 1st Embodiment. 4 is a graph showing the time dependence of the oxygen content of PbS quantum dots. It is a cross-sectional schematic diagram which shows an example of the manufacturing method of the photodetector based on 1st Embodiment. 4A to 4C are schematic cross-sectional views showing another example of the method for manufacturing the photodetector according to the first embodiment; It is a cross-sectional schematic diagram of the photodetector based on 2nd Embodiment. It is a cross-sectional schematic diagram of the photodetector based on 3rd Embodiment. It is a cross-sectional schematic diagram of the photodetector based on 4th Embodiment. It is a figure explaining operation|movement of the photodetection apparatus which concerns on 4th Embodiment. FIG. 12 is a diagram showing a configuration example of an imaging system according to a fifth embodiment; FIG. It is a figure which shows the structural example of the imaging system which concerns on 6th Embodiment, and a mobile body.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. All of the following embodiments show one configuration example of the present invention, and numerical values, shapes, materials, constituent elements, arrangement of constituent elements, connection relationships between constituent elements, etc. do not limit the present invention. do not have. For example, in the following embodiments, a photodetector is mainly shown as an example of a semiconductor device to which the present invention can be applied, but the present invention can also be applied to a light emitting device. Further, the conductivity types of transistors, semiconductor regions, etc. shown in the following embodiments can be changed as appropriate.

Further, in the following description and drawings, common reference numerals are assigned to common configurations across a plurality of drawings. The description of the configurations with common reference numerals may be omitted or simplified as appropriate.

[First embodiment]
FIG. 1 is a block diagram showing a schematic configuration of a photodetector according to this embodiment. The photodetector includes a pixel array 20 , vertical scanning circuit 30 , column amplifier circuit 40 , horizontal scanning circuit 50 , control circuit 60 and output circuit 70 . These circuits may be formed on one or more semiconductor substrates. Note that the photodetector of this embodiment is an imaging device that acquires an image, but is not limited to this. For example, the light detection device may be a focus detection device, a distance measurement device, a TOF (Time-Of-Flight) camera, or the like.

The pixel array 20 includes a plurality of pixels 10 arranged in a plurality of rows and a plurality of columns within the XY plane. The vertical scanning circuit 30 supplies control signals for turning on (conducting state) or off (non-conducting state) the transistors included in the pixels 10 via the control signal lines 6 provided in each row of the pixels 10 . A scanning circuit. The vertical scanning circuit 30 can be composed of a shift register or an address decoder. Here, since the control signal supplied to each pixel 10 can include a plurality of types of control signals, the control signal line 6 in each row can be configured as a set of a plurality of drive wirings. A column signal line 5 is provided for each column of the pixels 10, and signals from the pixels 10 are read out to the column signal line 5 for each column.

The column amplifier circuit 40 performs processing such as amplification of the pixel signal output to the column signal line 5 and correlated double sampling processing. The horizontal scanning circuit 50 provides control signals for turning on or off switches connected to the amplifiers of the column amplifier circuit 40 . The horizontal scanning circuit 50 can be composed of a shift register or an address decoder. The output circuit 70 is composed of a buffer amplifier, a differential amplifier, etc., and outputs the pixel signal from the column amplifier circuit 40 to a signal processing section outside the photodetector. It should be noted that the photodetector may be configured to output a digital image signal by further including an AD converter. For example, column amplifier circuit 40 may include an AD converter. The control circuit 60 controls operation timings of the vertical scanning circuit 30, the column amplifier circuit 40, and the horizontal scanning circuit 50, and the like.

FIG. 2 is a circuit diagram showing an example of the pixel 10 according to this embodiment. The pixel 10 includes a photoelectric conversion unit 11 , a floating diffusion (hereinafter referred to as FD) 12 , a reset transistor 14 , a source follower transistor (hereinafter referred to as SF transistor) 15 , a current source transistor 16 and a selection circuit 17 . These transistors can be composed of N-type MOS transistors having gate electrodes as control electrodes. Control signals PRES and PBIAS for controlling these transistors are input from the vertical scanning circuit 30 to the gates of the reset transistor 14 and the current source transistor 16 through the control signal line 6 .

The photoelectric conversion unit 11 is a photoelectric conversion element that generates an electric charge according to incident light by photoelectric conversion. The photoelectric conversion unit 11 can be configured by a photodiode including a photoelectric conversion layer. The anode of the photodiode forming the photoelectric conversion unit 11 is connected to an electrode having a potential VTOP.

The cathode of the photodiode, the source of the reset transistor 14, and the gate of the SF transistor 15, which constitute the photoelectric conversion unit 11, are connected to the FD12. The FD 12 has a capacitance, and this capacitance causes the potential of the FD 12 to change according to the charge generated in the photoelectric conversion section 11 .

A drain of the reset transistor 14 is connected to a potential line having a reset potential VRES. A drain of the SF transistor 15 is connected to a potential line having a reference potential SVDD. The source of the SF transistor 15 is connected to the drain of the current source transistor 16 and the input terminal of the selection circuit 17 . The source of current source transistor 16 is connected to a potential line having ground potential. The SF transistor 15 and current source transistor 16 constitute a source follower circuit. This source follower circuit outputs an output signal SFOUT based on the voltage of the FD 12 to the selection circuit 17 . Selection circuit 17 may include switches, sample-and-hold circuits, and the like. The selection circuit 17 has a function of selecting whether or not to output a signal based on the output signal SFOUT to the column signal line 5 according to the control signal from the vertical scanning circuit 30 . Thereby, the selection circuit 17 reads the output signal SFOUT at a predetermined timing, and outputs a signal corresponding to the output signal SFOUT to the column signal line 5 at a predetermined timing. The reset transistor 14 resets the potential of the FD 12 by being turned on. With the configuration described above, a signal corresponding to the charge generated in the photoelectric conversion unit 11 is output to the column signal line 5 .

The configuration of the pixel 10 shown in FIG. 2 is an example, and another circuit configuration may be used. FIG. 3 is a circuit diagram showing another example of the pixel 10 according to this embodiment. The pixel 10 further has a transfer transistor 13 in addition to the configuration of FIG. In this example, the cathode of the photodiode forming the photoelectric conversion unit 11 is connected to the source of the transfer transistor 13 . A drain of the transfer transistor 13 is connected to the FD12. A control signal PTX for controlling the transfer transistor 13 is input to the gate of the transfer transistor 13 from the vertical scanning circuit 30 via the control signal line 6 . The transfer transistor 13 transfers the charge of the photoelectric conversion unit 11 to the FD 12 by being turned on. The potential of the FD 12 changes according to the charges transferred from the photoelectric conversion section 11 . Thus, the pixel 10 may have the transfer transistor 13 that transfers the charge of the photoelectric conversion unit 11 to the FD 12 .

FIG. 4A is a schematic cross-sectional view of the photodetector according to this embodiment, and FIG. 4B is a schematic top view of the photodetector according to this embodiment. FIG. 4A shows a cross section of the photodetector on the XZ plane for only two pixels. FIG. 4(a) shows two adjacent pixels 10a and 10b. FIG. 4B shows a perspective view of the XY plane viewed from the Z direction of the photodetector for only two pixels.

The configuration of each part in FIG. 4A will be described in more detail. The photodetector device has a substrate 101 with a main surface P1. The material of the substrate 101 can be semiconductor, glass, ceramic, or the like. In this embodiment, the material of the substrate 101 is assumed to be a semiconductor made of silicon single crystal. A substrate 101 has a transistor 102 and an isolation portion 103 . Transistor 102 can be, for example, an N-type MOS transistor or a P-type MOS transistor. The element isolation portion 103 may be, for example, an STI structure (Shallow Trench Isolation).

Transistor 102 corresponds to any of the transistors shown in FIGS. The transistor 102 has source/drain regions 104 and 105 , a gate insulating film 106 and a gate electrode 107 . Source/drain regions 104 , 105 can be either the source and drain of transistor 102 . If the transistor 102 is an N-type MOS transistor, the source/drain regions 104 and 105 are N-type semiconductor regions. Gate electrode 107 is arranged on main surface P1. Gate insulating film 106 is arranged between gate electrode 107 and main surface P1. The source/drain regions 104 and the source/drain regions 105 are arranged inside the substrate 101 .

A wiring structure 110 is arranged on the main surface P<b>1 of the substrate 101 . The wiring structure 110 has contact plugs 111 , wiring layers 112 , via plugs 113 , wiring layers 114 , via plugs 115 and insulating films 116 . Although not shown in detail in FIG. 4A, the insulating film 116 may be a multilayer film composed of a plurality of layers.

The contact plug 111 and via plugs 113, 115 may be made of metal material. Specific examples of materials for the contact plug 111 and via plugs 113 and 115 include aluminum, copper, tungsten, titanium, titanium nitride, tantalum, and tantalum nitride. These materials may be laminated, and in this embodiment, the contact plug 111 may have a laminated structure of titanium, titanium nitride, and tungsten. Also, the via plug 113 may have a laminated structure of tantalum and copper, and the via plug 115 may have a laminated structure of titanium nitride, tantalum nitride, and tungsten. The wiring layers 112, 114 can be a metal material. Specific examples of materials for the wiring layers 112 and 114 include aluminum, copper, tungsten, titanium, titanium nitride, and tantalum. These materials may be laminated, and a laminated structure of tantalum and copper may be applied in this embodiment.

The insulating film 116 can include, for example, a film such as a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or the like. The silicon oxide film includes TEOS (Tetraethyl Orthosilicate), BPSG (Boron Phosphorus Silicate Glass), USG (Un-doped Silicate Glass), and the like. A silicon oxynitride film is a film containing silicon, oxygen, and nitrogen.

A first electrode 121 , interface layers 122 and 124 , a photoelectric conversion layer 123 , and a second electrode 125 that constitute the photoelectric conversion section 11 are arranged on the wiring structure 110 . A first electrode 121 is arranged directly above the wiring structure 110 so as to be electrically connected to the via plug 115 . The first electrode 121 is electrically connected to the transistor 102 through the wiring structure 110 . At least one first electrode 121 is included in each pixel. FIG. 4A shows a configuration in which one first electrode 121 is arranged for each pixel. An interface layer 122 is arranged on the first electrode 121 , and a photoelectric conversion layer 123 is arranged on the interface layer 122 . An interface layer 124 is arranged on the photoelectric conversion layer 123 , and a second electrode 125 is arranged on the interface layer 124 . The photoelectric conversion layer 123 includes a first portion 123 a arranged on the first electrodes 121 and a second portion 123 b arranged on the gaps 127 between the plurality of first electrodes 121 . In other words, the portion of the photoelectric conversion layer 123 that overlaps the first electrode 121 in vertical projection onto the main surface P is the first portion 123a, and the two adjacent first portions 123a that do not overlap the first electrode 121 is the second portion 123b.

Note that the first electrode 121 in FIG. 4A corresponds to the cathode of the photoelectric conversion section 11 in FIG. 2 or 3 . The second electrode 125 in FIG. 4A corresponds to the anode of the photoelectric conversion section 11 in FIG. 2 or 3 .

The first electrode 121 and the second electrode 125 can be made of any conductive material. Specific examples of constituent materials of the first electrode 121 and the second electrode 125 include metals such as platinum, gold, silver, aluminum, chromium, nickel, copper, titanium, magnesium, and alloys thereof. Further, another specific example of the constituent material of the first electrode 121 and the second electrode 125 includes metal oxides such as indium oxide and tin oxide, and composite oxides thereof (eg, ITO and IZO). Still another specific example of the constituent material of the first electrode 121 and the second electrode 125 includes conductive particles such as carbon black, fullerene, carbon nanotube, and graphene. Also, the constituent material of the first electrode 121 and the second electrode 125 may be a conductive composite material obtained by dispersing these conductive particles in a matrix such as a polymer binder. For the electrode, one material may be used alone, or two or more materials may be used together in any combination and ratio.

In the photodetector, a pair (two) of electrodes may be provided. At this time, at least one of the pair of electrodes is preferably transparent. This allows incident light to pass through the electrodes and be absorbed by the photoelectric conversion layer 123 . The electrode has a function of collecting electrons and holes generated inside the photoelectric conversion layer 123 . Therefore, among the materials described above, it is preferable to use a material suitable for trapping electrons and holes as a constituent material of the electrode. Electrode materials suitable for collecting holes include, for example, materials having a high work function such as gold and ITO. On the other hand, an electrode material suitable for collecting electrons includes, for example, a material having a low work function, such as aluminum. The thickness of the electrode is not particularly limited, and can be appropriately determined in consideration of the material used, required conductivity, transparency, etc., but is usually about 10 nm to 10 μm.

The interface layers 122 and 124 are electrically conductive between the first electrode 121 and the photoelectric conversion layer 123 or between the second electrode 125 and the photoelectric conversion layer 123 for some carriers, that is, carriers of either holes or electrons. This layer is for ensuring insulation. That is, the interface layer 122 is a layer that ensures conduction between the first electrode 121 and the photoelectric conversion layer 123 for the other carriers, and the interface layer 124 is provided between the second electrode 125 and the photoelectric conversion layer 123. It is a layer that secures conduction with respect to the other carrier. Therefore, it can be said that the interface layers 122 and 124 are carrier injection blocking layers. Normally, a layer (electron blocking interface layer) that blocks electrons and conducts only holes is disposed on the electrode (positive electrode) that collects holes, and the electrode (negative electrode) that collects electrons has A layer that blocks holes and conducts only electrons (hole-blocking interface layer) is provided. The thickness of the interfacial layers 122, 124 may be on the order of 1 nm to 100 nm. By applying an electric field in the film thickness direction of the interface layers 122 and 124, charge injection can be controlled.

The material of the electron block interface layer is preferably a material capable of efficiently transporting holes generated in the photoelectric conversion layer 123 to the positive electrode. More specifically, high hole mobility, high electrical conductivity, a small hole injection barrier between the electron-blocking interface layer and the positive electrode, It preferably has properties such as a small hole injection barrier. Furthermore, in the case of a structure in which light is incident on the photoelectric conversion layer 123 through the electron block interface layer, the material of the electron block interface layer is preferably a highly transparent material. When visible light is incident on the photoelectric conversion layer 123 through the electron-blocking interface layer, the transmittance of the electron-blocking interface layer is generally preferably 60% or more, more preferably 80% or more. From the above viewpoints, examples of suitable materials for the electron block interface layer include inorganic semiconductors such as molybdenum oxide (MoO ₃ ) and nickel oxide (NiO), or P-type semiconductor materials such as organic PEDOT:PSS. are mentioned.

On the other hand, the function required for the hole-blocking interface layer is to block holes separated from the photoelectric conversion layer 123 and transport electrons to the negative electrode. Therefore, the properties of the material that can be suitably used for the hole-blocking interface layer can be obtained by replacing holes with electrons, positive electrodes with negative electrodes, and P-type semiconductors with N-type semiconductors in the above description of the electron-blocking interface layer. It is a thing. In addition, in the case of a configuration in which light is incident from the negative electrode side or a configuration in which light reflected by the negative electrode side is photoelectrically converted, high transmittance may be required in that case. From the above viewpoints, examples of suitable materials for the hole block interface layer include inorganic N-type wide bandgap semiconductor materials such as titanium oxide (TiO ₂ ) and zinc oxide (ZnO), fullerene (C ₆₀ ), and the like. of N-type semiconductor materials.

The photoelectric conversion layer 123 may be composed of an inorganic material or an organic material. Examples of the inorganic material forming the photoelectric conversion layer 123 include colloidal quantum dots, which are nanoparticles of a semiconductor material. Colloidal quantum dots contain nanoparticles having an average particle size of 0.5 nm or more and less than 100 nm. The material of the nanoparticles may be a Group IV semiconductor, or a Group III-V or Group II-VI compound semiconductor, containing elements of Groups II, III, IV, V and VI elements. A compound semiconductor consisting of a combination of three or more of them may be used. Specific examples include semiconductor materials such as PbS, PbSe, PbTe, InN, InAs, InP, InSb, InGaAs, CdS, CdSe, CdTe, Ge, CuInS, CuInSe, CuInGaSe, and Si. These are relatively narrow bandgap semiconductor materials. These are also called semiconductor quantum dots. The colloidal quantum dots may contain nanoparticles of only one of the above materials, or may contain nanoparticles of two or more kinds. The structure of the nanoparticles may be a core-shell structure in which the above material is used as a nucleus (core) and the nucleus is covered with a coating compound.

The size of the nanoparticles can be set at or below the size of the exciton Bohr radius specific to each semiconductor material. In this case, a desired bandgap corresponding to the size is obtained due to the quantum size effect. That is, by controlling the size of nanoparticles to a predetermined value during manufacture, the light absorption wavelength or emission wavelength can be controlled.

The material used for the nanoparticles is preferably PbS or PbSe from the viewpoint of ease of synthesis. Since the exciton Bohr radius of PbS is approximately 18 nm, the average particle size of the nanoparticles is preferably in the range of 2 nm to 15 nm from the viewpoint of crystal growth control and quantum size effect. A transmission electron microscope can be used to measure the size of the nanoparticles. By setting the average particle size of the nanoparticles to 2 nm or more, it becomes easier to control the crystal growth in the synthesis of the nanoparticles.

Although the thickness of the photoelectric conversion layer 123 is not particularly limited, it is preferably 10 nm or more, more preferably 50 nm or more, from the viewpoint of obtaining high light absorption characteristics. Moreover, from the viewpoint of ease of manufacture, the film thickness of the photoelectric conversion layer 123 is preferably 800 nm or less.

An example of the organic material (organic photoelectric conversion material) forming the photoelectric conversion layer 123 includes a bulk heterojunction formed by a blend of a donor conjugated polymer and an acceptor fullerene derivative. An example of a donor conjugated polymer is poly(3-hexylthiophene-2,5-diyl) (P3HT). An example of an acceptor fullerene derivative is phenyl _C61 butyric acid methyl ester (PCBM).

In FIG. 4A, an insulating layer 126 is arranged on the second electrode 125 . Furthermore, on the insulating layer 126, a color filter layer (not shown), a planarizing layer, and a microlens layer can be arranged in this order. Insulating layer 126 may function as a protective layer and an encapsulating layer. The color filter layer has color filters corresponding to any of a plurality of colors. A color filter selectively transmits light of a predetermined color. For example, one pixel 10 can include one color filter. A planarization layer is provided on the color filter layer and has a planar upper surface. The microlens layer has a plurality of microlenses. The microlens converges incident light onto the photoelectric conversion unit 11 . For example, one pixel can include one microlens. Note that the configuration described here is just an example, and one color filter may be arranged for two or more adjacent pixels 10 . Also, one microlens may be arranged for two or more adjacent pixels 10 .

FIG. 4B shows the positional relationship between the first electrode 121, the first portion 123a, and the second portion 123b. In FIG. 4B, elements other than the first electrode 121, the first portion 123a, and the second portion 123b are omitted. As shown in FIG. 4B, the plurality of first electrodes 121 are rectangular extending in the Y direction. A second portion 123 b of the photoelectric conversion layer 123 is arranged on the gap 127 between the plurality of first electrodes 121 . The second portion 123b is arranged to surround the plurality of first electrodes 121 and the plurality of first portions 123a in plan view. Although only two first electrodes 121 aligned in the X direction are shown in FIG. 4A, a plurality of first electrodes 121 are also aligned in the Y direction. The second portion 123b is also arranged above the gap 127 between the two first electrodes 121 arranged side by side in the Y direction.

As described above, the photoelectric conversion layer 123 includes the first portion 123a arranged on the first electrode 121 and the second portion 123b arranged on the gap 127 between the plurality of first electrodes 121. include. Here, the oxygen content per unit volume in the second portion 123b is higher than the oxygen content per unit volume in the first portion 123a. Here, the standard for the content may be the content on a molar basis. That is, the molar content of oxygen in the second portion 123b is higher than the molar content of oxygen in the first portion 123a.

The effect of setting the oxygen content of the photoelectric conversion layer 123 as described above will be described. FIGS. 5A and 5B are schematic cross-sectional views for explaining the effect of the photodetector according to this embodiment. FIG. 5(a) is a schematic cross-sectional view of a comparative example in which there is no difference in oxygen content between the first portion 123a and the second portion 123b, and FIG. 5(b) is a schematic cross-sectional view of this embodiment.

FIG. 5A schematically shows movement of carriers 131 , 132 , and 133 generated in the photoelectric conversion layer 123 . Carriers 133 generated at positions laterally (X-direction) away from the gap 127 are collected by the first electrode 121 near where they are generated. Also, even if it is close to the gap 127 , the carriers 132 generated in the immediate vicinity of the first electrode 121 are collected by the nearby first electrode 121 . However, the carriers 131 generated at a position far from the first electrode 121 and close to the gap 127 move laterally from the position of the pixel 10a where the carriers 131 are generated, and move to the first electrode 121 of the adjacent pixel 10b. may be captured by Such carriers 131 can cause crosstalk between pixels.

In contrast, as shown in FIG. 5B, in the configuration in which the second portion 123b having a high oxygen content is arranged above the gap 127, the carriers 131 generated in the pixel 10a are trapped in the second portion 123b. Therefore, it becomes difficult to move to the pixel 10b side. This may reduce crosstalk between pixels.

The reason why the second portion 123b having a high oxygen content traps carriers will be described. In the following description, as an example, the photoelectric conversion layer 123 is assumed to be a colloidal quantum dot (hereinafter referred to as a PbS quantum dot) mainly made of PbS nanoparticles. The quantum efficiency of PbS quantum dots decreases when there are oxides such as PbSO ₂ , PbSO ₃ and PbSO ₄ on the surface of the quantum dots. The reason for this is thought to be that oxides such as PbSO ₂ , PbSO ₃ and PbSO ₄ form trap levels within the bandgap. Therefore, it is considered that when carriers 131 approach second portion 123b containing a large amount of oxide, carriers 131 are trapped in trap levels caused by oxide.

The quantum efficiency of PbS quantum dots decreases when left in the air near a fluorescent lamp, and the quantum efficiency decreases to ⅛ or less after being left for one day. This is because oxides such as PbSO ₂ , PbSO ₃ and PbSO ₄ are formed on the surface of the PbS quantum dots by photo-oxidation by the light of the fluorescent lamp, and trap levels are formed in the bandgap. guessed. FIG. 6 is a graph showing the time dependence of the oxygen content of PbS quantum dots. The graph of FIG. 6 shows the results of measuring the oxygen (O) content by XPS (X-ray Photoelectron Spectroscopy) after leaving the PbS quantum dots in the air under a fluorescent lamp. The vertical axis indicates the value of O peak [c/s] (the number of counts per second at the peak indicating oxygen). The higher the O peak [c/s], the higher the oxygen (O) content in the sample. The horizontal axis indicates the number of days the sample was left in the air near the fluorescent lamp, and the initial value (after 0 days), after 7 days, and after 14 days are plotted.

When the oxygen content after one day is calculated from the approximation formula obtained from these data, the oxygen content after one day is 1.5 times the initial oxygen content. In order to reduce crosstalk more effectively, the quantum efficiency is preferably ⅛ or less, which corresponds to oxidation caused by being left in the air near a fluorescent lamp for one day. Therefore, it is preferable that the oxygen content of the second portion 123b is at least 1.5 times higher than the oxygen content of the first portion 123a.

It is known that P3HT and PCBM described above as the organic materials of the photoelectric conversion layer 123 are reduced in quantum efficiency by photo-oxidation, similarly to the quantum dots of PbS. As described above, the material of the photoelectric conversion layer 123 is not limited to PbS quantum dots, and may be any material that can reduce crosstalk by increasing the oxygen content of the second portion 123b.

Next, an example of a method for manufacturing the photodetector according to this embodiment will be described. 7A, 7B, and 7C are schematic cross-sectional views showing an example of the method for manufacturing the photodetector according to this embodiment.

First, the process up to the formation of the photoelectric conversion layer 123 will be described with reference to FIG. First, the substrate 101 is prepared. After that, a transistor is formed on the substrate 101 and a wiring structure 110 is formed thereon by a general semiconductor device manufacturing process. Next, a first electrode 121 is formed on the wiring structure 110, and an interface layer 122 is formed thereon. A vapor deposition method or a sputtering method can be used to form the interface layer 122 . After that, a photoelectric conversion layer 123 is formed on the interface layer 122 to obtain the structure shown in FIG.

Next, the photo-oxidation process of the photoelectric conversion layer 123 will be described with reference to FIG. 7(b). As shown in FIG. 7B, the substrate 101 is loaded into an apparatus having a light source such as an exposure apparatus for photolithography, and a mask 141 is placed on the photoelectric conversion layer 123 . The mask 141 is formed with a pattern such that incident light is blocked at a portion corresponding to the first portion 123a and incident light is transmitted at a portion corresponding to the second portion 123b. After that, the photoelectric conversion layer 123 is irradiated with light from a light source of an exposure apparatus in an atmosphere containing oxygen. Light entering the first portion 123a is blocked by the mask 141 . A larger amount of light is incident on the second portion 123b than on the first portion 123a, further promoting photo-oxidation. Therefore, the oxygen content in the second portion 123b is higher than the oxygen content in the first portion 123a.

As the light source, a light source generally used in an exposure apparatus for photolithography can be used. Specifically, the light source includes g-line (wavelength 436 nm) of an ultra-high pressure mercury lamp, i-line (wavelength 365 nm) of an ultra-high pressure mercury lamp, KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), and the like. can be used.

Next, with reference to FIG. 7(c), the process after the photo-oxidation process will be described. After the photo-oxidation process, an interface layer 124 and a second electrode 125 are formed on the photoelectric conversion layer 123 . A vapor deposition method or a sputtering method can be used to form the interface layer 124 . After that, an insulating layer 126, a color filter layer (not shown), a planarization layer (not shown) and a microlens layer (not shown) are sequentially formed. A general manufacturing process of a semiconductor device can be applied to the manufacturing method of each of these layers.

At some point after the formation of the photoelectric conversion layer 123, annealing is performed to improve photoelectric conversion efficiency and carrier injection. The annealing temperature is determined in consideration of the heat resistance of the material used for each layer. If organic materials are used in the photodetector, this temperature is set below the lowest glass transition temperature of the organic materials. Also, these organic materials must be durable enough to the temperatures that can be applied in each process of the photodetector. Therefore, the glass transition temperature of those organic materials is preferably 100° C. or higher.

Next, another example of the method for manufacturing the photodetector according to this embodiment will be described. 8(a), 8(b), 8(c) and 8(d) are schematic cross-sectional views showing another example of the method for manufacturing the photodetector according to the present embodiment. The processes up to the formation of the photoelectric conversion layer 123 shown in FIG. 8A are the same as those in FIG.

A process of forming the sacrificial film 142 after forming the photoelectric conversion layer 123 will be described with reference to FIG. After forming the photoelectric conversion layer 123 , an interface layer 124 , a second electrode 125 a and a sacrificial film 142 are formed on the photoelectric conversion layer 123 . Here, for the sacrificial film 142, a material that absorbs the light of the wavelength of the light source used for photo-oxidation is used. More specifically, a photoresist for photolithography can be used for the sacrificial film 142 . Thereby, the pattern of the sacrificial film 142 can be easily formed. It is assumed below that the sacrificial film 142 is a photoresist.

Next, the photo-oxidation process of the photoelectric conversion layer 123 will be described with reference to FIG. 8(c). First, a portion of the sacrificial film 142 corresponding to the second portion 123b is removed by processing the sacrificial film 142 by photolithography. Thereafter, using the sacrificial film 142 as a mask, the interface layer 124 and the second electrode 125a are etched by dry etching or wet etching, thereby transferring the pattern of the sacrificial film 142 to the interface layer 124 and the second electrode 125a. As a result, the interface layer 124 and the second electrode 125a are opened at positions corresponding to the second portions 123b. After that, the photoelectric conversion layer 123 is irradiated with light from a light source such as a UV irradiation device in an atmosphere containing oxygen. The sacrificial film 142 shields light incident on the first portion 123a. Therefore, a larger amount of light is incident on the second portion 123b than on the first portion 123a, further promoting photo-oxidation. Therefore, the oxygen content in the second portion 123b is higher than the oxygen content in the first portion 123a.

Next, with reference to FIG. 8(d), processes after the photo-oxidation process will be described. After the photo-oxidation process, the sacrificial film 142 is removed to form the second electrode 125b. The second electrode 125b may be of the same material as the second electrode 125a. By forming the second electrode 125b and short-circuiting the plurality of second electrodes 125a separated by etching, the potential VTOP in FIG. 2 or 3 becomes the same potential among the plurality of pixels. After that, an insulating layer 126, a color filter layer (not shown), a planarization layer (not shown) and a microlens layer (not shown) are sequentially formed.

As described above, in the present embodiment, the photoelectric conversion layer 123 is arranged on the first portion 123 a arranged on the first electrode 121 and the first portion 123 a arranged on the gap 127 between the plurality of first electrodes 121 . and two portions 123b. In the process of photo-oxidation, a larger amount of light is incident on the second portion 123b than on the first portion 123a. As a result, the molar content of oxygen in the second portion 123b is higher than the molar content of oxygen in the first portion 123a. With such a configuration, crosstalk between pixels is reduced in the photodetector of this embodiment. Therefore, according to this embodiment, a semiconductor device with reduced crosstalk and a method for manufacturing the semiconductor device are provided.

[Second embodiment]
A photodetector according to the second embodiment will be described. The difference of the photodetector of this embodiment from the photodetector of the first embodiment is the depth direction distribution of the oxygen content in the second portion 123b.

FIG. 9 is a schematic cross-sectional view of the photodetector according to this embodiment. The difference of FIG. 9 with respect to FIG. 4(a) is the second portion 123b. In the first embodiment, as shown in FIG. 4A, the entire second portion 123b is photo-oxidized, and the oxygen content in the second portion 123b varies in the depth direction (perpendicular to the main surface P1 of the substrate 101). direction). That is, in the first embodiment, the entire second portion 123b is a highly oxidized portion having a higher molar oxygen content than the first portion 123a. On the other hand, this embodiment differs from the first embodiment in that the highly oxidized portion is partially arranged in the second portion 123b. More specifically, in the present embodiment, as shown in FIG. 9, the second portion 123b includes a highly oxidized portion 123b1 having a higher molar oxygen content than the first portion 123a and a highly oxidized portion 123b1. and a low oxidation portion 123b2 having a lower content of oxygen on a molar basis than the lower oxidation portion 123b2. The molar content of oxygen in the low oxidation portion 123b2 may be the same as the molar content of oxygen in the first portion 123a. In this embodiment, the existence ratio of the highly oxidized portion 123b1 in the second portion 123b is higher toward the second electrode 125 side and lower toward the first electrode 121 side. Thus, in the present embodiment, the oxygen content in the second portion 123b is higher in the depth direction closer to the second electrode 125 side, and is lower in the depth direction closer to the first electrode 121 side. there is

Here, as shown in FIG. 9, the existence ratio of the highly oxidized portion 123b1 in the second portion 123b has been described as gradually increasing toward the second electrode 125 side, but the present invention is not limited to this. For example, the existence ratio of the highly oxidized portion 123b1 in the second portion 123b may increase stepwise toward the second electrode 125 side.

As shown in FIGS. 5(a) and 5(b), the carriers 131 generated near the second electrode 125 tend to move in the lateral direction. It is desirable to increase the existence ratio of the highly oxidized portion 123b1 to enhance the carrier collection effect. On the other hand, the carriers 132 generated in the immediate vicinity of the first electrode 121 are likely to be collected by the nearby first electrode 121, and are less likely to cause crosstalk. Therefore, the existence ratio of the highly oxidized portion 123b1 may be relatively low at a position close to the first electrode 121. FIG. Rather, by increasing the existence ratio of the low-oxidized portion 123b2 at a position close to the first electrode 121, the amount of the photoelectric conversion layer 123 that contributes to photoelectric conversion can be increased, and the photoelectric conversion efficiency can be improved. can be done. Considering the above properties, in the second portion 123b, the presence ratio of the highly oxidized portion 123b1 is higher toward the second electrode 125 side and lower toward the first electrode 121 side. Crosstalk can be reduced while suppressing a decrease in conversion efficiency. Therefore, according to the present embodiment, a semiconductor device and a method for manufacturing a semiconductor device are provided in which crosstalk is further reduced while suppressing a decrease in photoelectric conversion efficiency.

[Third Embodiment]
A photodetector according to the third embodiment will be described. The difference of the photodetector of this embodiment from the photodetector of the first embodiment is the depth direction distribution of the oxygen content in the second portion 123b.

FIG. 10 is a schematic cross-sectional view of the photodetector according to this embodiment. The difference of FIG. 10 with respect to FIG. 4(a) is the second portion 123b. The gradation of the second portion 123b shown in FIG. 10 indicates that the molar content of oxygen in the second portion 123b is higher the closer to the second electrode 125 and lower the closer to the first electrode 121. Schematically. Therefore, in the present embodiment as well, the oxygen content in the second portion 123b is higher as it is closer to the second electrode 125 side in the depth direction, and is lower as it is closer to the first electrode 121 side in the depth direction. there is

Also in the configuration of this embodiment, for the same reason as in the second embodiment, the carrier collection efficiency is improved, so crosstalk can be reduced more efficiently. Therefore, according to the present embodiment, a semiconductor device and a method for manufacturing a semiconductor device with reduced crosstalk are provided.

As in the second embodiment, a highly oxidized portion 123b1 and a lowly oxidized portion 123b2 are arranged in the second portion 123b, and the oxygen content in the highly oxidized portion 123b1 is decreased as it is closer to the first electrode 121 as in the present embodiment. You may make it

It should be noted that the distribution of oxygen in the second portion 123b as shown in the second and third embodiments is such that the focal point of the irradiation light is changed in the light irradiation step for photo-oxidation described in the first embodiment. It is realized by setting above the upper surface of the photoelectric conversion layer 123 .

[Fourth Embodiment]
A photodetector according to the fourth embodiment will be described. The difference of the photodetector of this embodiment from the photodetector of the first embodiment is that a third electrode 128 for discharging carriers accumulated in the second portion 123b is arranged between the plurality of first electrodes 121. The point is that

FIG. 11 is a schematic cross-sectional view of the photodetector according to this embodiment. The difference of FIG. 11 from FIG. 4A is that third electrodes 128 are arranged between the plurality of first electrodes 121 . The interface layer 122 is arranged on the third electrode 128 , and the photoelectric conversion layer 123 is arranged on the interface layer 122 . The photoelectric conversion layer 123 on the third electrode 128 generally corresponds to the second portion 123b. 11, illustration of the substrate 101 and the wiring structure 110 is omitted.

12A and 12B are diagrams for explaining the operation of the photodetector according to this embodiment. The operation of the photodetector will be described with mutual reference to FIGS. 12(a) and 12(b). FIG. 12A is a circuit diagram showing an example of a pixel according to this embodiment.

The circuit of FIG. 12A further includes a photoelectric conversion section 18 and a reset transistor 19 in addition to the circuit of FIG. The photoelectric conversion section 18 is equivalent to a photodiode corresponding to the second portion 123 b of the photoelectric conversion layer 123 . The reset transistor 19 is a transistor that discharges carriers from the third electrode 128 and resets the potential of the third electrode 128 .

The anode of the photodiode forming the photoelectric conversion section 18 is connected to an electrode having the potential VTOP. This anode corresponds to the second electrode 125 . The cathode of the photodiode that constitutes the photoelectric conversion unit 18 is a node corresponding to the third electrode 128 and is connected to the source of the reset transistor 19 . A drain of the reset transistor 19 is connected to a potential line having a reset potential VRES. A control signal PRES<b>2 for controlling these transistors is input to the gate of the reset transistor 19 from the vertical scanning circuit 30 via the control signal line 6 . The control signal input to the gate of the reset transistor 14 is denoted as control signal PRES1 in this embodiment.

FIG. 12(b) is a timing chart showing the outline of the operation of the pixel according to this embodiment. PBIAS, PRES1, and PRES2 in FIG. 12(b) indicate the levels of the corresponding control signals. FD in FIG. 12B indicates the potential of the FD 12, and SFOUT indicates the potential of the output signal of the source follower circuit composed of the SF transistor 15 and the current source transistor 16. FIG. The potential of the output signal SFOUT is lower than the potential of the FD 12 by the gate-source voltage of the SF transistor 15 .

The time t0 is an arbitrary time after the start of charge accumulation in the photoelectric conversion unit 11 already. At time t1, the control signal PBIAS changes from low level to high level, and the current source transistor 16 is turned on. The high level of control signal PBIAS is set so that current source transistor 16 operates as a current source that outputs a desired current.

The selection circuit 17 is controlled such that the potential of the output signal SFOUT is read out at an arbitrary timing between time t1 and time t2. Next, at time t2, the control signals PRES1 and PRES2 change from low level to high level, and the reset transistors 14 and 19 are turned on. As a result, the potential of the FD12 becomes the reset potential VRES, and the potential of the output signal SFOUT also changes to a potential corresponding to the reset potential VRES. Further, carriers in the second portion 123b of the photoelectric conversion layer 123 are discharged.

Note that FIG. 12B shows an example in which the periods during which the control signals PRES1 and PRES2 are high level overlap. That is, the period during which the reset transistor 19 (first transistor) is turned on and the period during which the reset transistor 14 (second transistor) is turned on overlap. By at least partially overlapping these periods, carriers in the second portion 123b of the photoelectric conversion layer 123 can be discharged during the reset period of the FD 12 . This can reduce the influence on the output signal caused by the discharge of carriers trapped in the second portion 123 b from the third electrode 128 . However, this is not essential and the timing of the control signals PRES1, PRES2 may be different.

Next, at time t3, the control signals PRES1 and PRES2 change from high level to low level, and the reset transistors 14 and 19 are turned off. This restarts the charge accumulation. Also, at the timing when the reset transistors 14 and 19 are turned off, the potential of the FD 12 and the potential of the output signal SFOUT change due to coupling due to parasitic capacitance between the gate and source. Next, at time t4, the control signal PBIAS changes from high level to low level, and the current source transistor 16 is turned off.

It should be noted that the configuration may be such that a signal corresponding to the noise level of the photoelectric conversion unit 11 is read at arbitrary timing. Alternatively, as shown in FIG. 3, the cathode side of the photoelectric conversion unit 11 may be connected to the FD 12 via the transfer transistor 13. FIG.

It is considered that the carriers trapped in the second portion 123b having a high oxygen content may be re-released after a certain period of time. Re-emitted carriers can appear as a residual image in the output image of the photodetector. Thus, carriers trapped in the second portion 123b can cause noise. In this embodiment, the configuration is such that the carriers trapped in the second portion 123b can be discharged from the third electrode 128. FIG. Therefore, according to the present embodiment, in addition to the effects of the first embodiment, an effect of reducing noise caused by carriers captured by the second portion 123b can be obtained.

The timing at which the control signal PRES2 goes high takes into consideration the time required for the re-emission of the carriers captured by the second portion 123b, the timing for reading out the signal based on the charges generated by the first portion 123a, and the like. It can be set as appropriate. This effectively reduces noise such as afterimages.

[Fifth embodiment]
The semiconductor device (photodetector) described in the above first to fourth embodiments can be used as a photoelectric conversion element that outputs a signal corresponding to incident light through photoelectric conversion. A photoelectric conversion element can be used, for example, as a light receiving element that detects light. The light receiving element has a photoelectric conversion element including the semiconductor device according to the above-described first to fourth embodiments, and a signal processing circuit that processes a signal generated by the photoelectric conversion element.

Moreover, the photoelectric conversion element described above may be used in an imaging system that generates an image according to incident light. An imaging system has an optical system having a plurality of lenses and an imaging device that receives light that has passed through the optical system. An imaging device includes the photoelectric conversion element described above. The imaging system can be specifically a digital still camera, a digital video camera. A device including a photoelectric conversion device such as the light receiving device and imaging system described above may be generically called a photoelectric conversion device.

A configuration example of an imaging system will be described below as a fifth embodiment of the present invention. FIG. 13 is a diagram showing a configuration example of an imaging system 500 according to this embodiment. The imaging system 500 includes an imaging device 530 , an imaging optical system 502 , a CPU 510 , a lens control unit 512 , an imaging device control unit 514 , an image processing unit 516 , an aperture shutter control unit 518 , a display unit 520 , an operation switch 522 and a recording medium 524 . Prepare.

The imaging optical system 502 is an optical system for forming an optical image of a subject by guiding incident light to an imaging device 530, and includes a lens group, a diaphragm 504, and the like. The diaphragm 504 has a function of adjusting the amount of light at the time of shooting by adjusting its aperture diameter, and also has a function of a shutter for adjusting the exposure time when shooting a still image. The lens group and the diaphragm 504 are held so as to move forward and backward along the optical axis direction, and their interlocking operation realizes a variable power function (zoom function) and a focus adjustment function. The imaging optical system 502 may be integrated with the imaging system 500 or may be an imaging lens attachable to the imaging system 500 .

An imaging device 530 is arranged in the image space of the imaging optical system 502 . The imaging device 530 includes a CMOS sensor (pixel portion) including the semiconductor device according to the above-described first to fourth embodiments, and its peripheral circuit (peripheral circuit region). The imaging device 530 has a structure in which a plurality of unit cells are arranged two-dimensionally. Each of the plurality of unit cells has a color filter of a predetermined color. Thus, the imaging device 530 constitutes a two-dimensional single-plate color sensor. The imaging device 530 photoelectrically converts the subject image formed by the imaging optical system 502 and outputs it as an image signal or a focus detection signal.

A lens control unit 512 controls the forward/backward drive of the lens group of the imaging optical system 502 to perform zooming and focus adjustment. The lens control unit 512 is composed of circuits and processing devices configured to realize these functions. A diaphragm/shutter control unit 518 changes the aperture diameter (aperture value) of the diaphragm 504 to adjust the amount of photographing light. The lens control unit 512 and the aperture/shutter control unit 518 are configured by circuits or processing devices configured to realize their functions.

A CPU 510 is an in-camera control device that controls various aspects of the camera body, and includes an arithmetic unit, ROM, RAM, A/D converter, D/A converter, communication interface circuit, and the like. The CPU 510 controls the operation of each unit in the camera according to a computer program stored in the ROM or the like, and executes a series of photographing operations such as AF, imaging, image processing, and recording. AF operations that can be executed by the CPU 510 include detection of the focus state of the imaging optical system 502 (focus detection). The CPU 510 can also function as a signal processing section.

The imaging device control unit 514 controls the operation of the imaging device 530 , A/D-converts a signal output from the imaging device 530 , and transmits the signal to the CPU 510 . The imaging device control unit 514 is configured by a circuit or control device configured to realize those functions. Note that the A/D conversion function may be provided in the imaging device 530 instead of the imaging device control section 514 . An image processing unit 516 performs image processing such as γ conversion and color interpolation on the A/D converted signal to generate an image signal.

The image processing unit 516 is configured by a circuit or control device configured to realize those functions. A display unit 520 is a display device such as a liquid crystal display (LCD), and displays information regarding the photographing mode of the camera, a preview image before photographing, a confirmation image after photographing, an in-focus state during focus detection, and the like. The operation switch 522 includes a power switch, a release (shooting trigger) switch, a zoom operation switch, a shooting mode selection switch, and the like. A recording medium 524 is for recording captured images and the like. The recording medium 524 may be built in the imaging system 500, or may be removable such as a memory card.

As described above, according to this embodiment, the high-performance imaging system 500 can be realized by applying the semiconductor devices according to the first to fourth embodiments.

[Sixth Embodiment]
The semiconductor devices according to the above-described first to fourth embodiments can be used in mobile objects. The moving body has a main body provided with photoelectric conversion elements including the semiconductor devices according to the above-described first to fourth embodiments, and moving means for moving the main body. Specific examples of mobile objects include automobiles, aircraft, ships, and drones. The photoelectric conversion element can image the surroundings of the main body. The captured images may be used in support of mobile operation. The body may be constructed of materials such as metal, carbon fiber, and the like. Carbon fibers can be, for example, polycarbonate or the like. Specific examples of moving means include tires, magnetic floating devices, and mechanisms for vaporizing and injecting fuel.

FIGS. 14A and 14B are diagrams showing configuration examples of an imaging system and a moving body according to this embodiment. FIG. 14(a) shows an example of an imaging system 400 for an in-vehicle camera. The imaging system 400 has an imaging device 410 , an image processing section 412 , a parallax acquisition section 414 , a distance acquisition section 416 and a collision determination section 418 . The imaging device 410 includes the semiconductor device according to the first to fourth embodiments described above, and generates image data according to incident light. The image processing unit 412 is a processing device that performs image processing on a plurality of image data acquired by the imaging device 410 . The parallax acquisition unit 414 is a processing device that calculates parallax (phase difference of parallax images) from a plurality of image data acquired by the imaging device 410 . Further, the distance acquisition unit 416 is a processing device that calculates the distance to the object based on the calculated parallax. The collision determination unit 418 is a processing device that determines whether there is a possibility of collision based on the calculated distance. Here, the parallax acquisition unit 414 and the distance acquisition unit 416 are examples of information acquisition means for acquiring information such as distance information to the object. That is, the distance information is information related to parallax, defocus amount, distance to the object, and the like.

Collision determination unit 418 may determine the possibility of collision using any of these distance information. The various processing devices described above may be realized by specially designed hardware, or may be realized by general-purpose hardware that performs calculations based on software modules. Also, the processing device may be realized by FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit), or the like. Also, the processing device may be realized by a combination of these.

The imaging system 400 is connected to a vehicle information acquisition device 420, and can acquire vehicle information such as vehicle speed, yaw rate, and steering angle. Further, the imaging system 400 is connected to a control ECU 430 which is a control device that outputs a control signal for generating a braking force to the vehicle based on the determination result of the collision determination section 418 . In other words, the control ECU 430 is an example of mobile body control means for controlling the mobile body based on the distance information. The imaging system 400 is also connected to an alarm device 440 that issues an alarm to the driver based on the determination result of the collision determination section 418 . For example, when the collision determination unit 418 outputs a determination result indicating that there is a high possibility of collision, the control ECU 430 applies the brake, releases the accelerator, suppresses the engine output, etc. to avoid the collision and prevent damage. Vehicle control to mitigate. The alarm device 440 warns the user by sounding an alarm such as sound, displaying alarm information on a screen of a car navigation system or the like, or vibrating a seat belt, a steering wheel, or the like.

In this embodiment, the imaging system 400 images the surroundings of the vehicle, for example, the front or the rear. FIG. 14(b) shows the configuration of the imaging system 400 when imaging the front of the vehicle (imaging range 450). Vehicle information acquisition device 420 sends an instruction to imaging system 400 to perform imaging.

As described above, according to the present embodiment, by applying the semiconductor devices according to the first to fourth embodiments, it is possible to realize an imaging system and a moving object with further improved distance measurement accuracy.

In the above description, an example of controlling the vehicle so as not to collide with another vehicle has been described. It can also be applied to control and the like. Furthermore, the imaging system 400 can be applied not only to vehicles such as automobiles, but also to moving bodies (transportation equipment) such as ships, aircraft, and industrial robots. Moving devices in moving bodies (transportation equipment) are various moving means such as engines, motors, wheels, and propellers. In addition, the imaging system 400 of the present embodiment can be applied not only to mobile objects but also to devices that widely use object recognition, such as intelligent transportation systems (ITS).

[Modified embodiment]
The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, a form in which a part of the configuration of any one of the embodiments is added to another embodiment, or a form in which a part of the configuration of another embodiment is replaced is also an embodiment of the present invention.

Further, the imaging systems shown in the above-described embodiments are examples of imaging systems to which the semiconductor device of the present invention can be applied. 14(a) and 14(b).

It should be noted that the above-described embodiments are merely examples of specific implementations of the present invention, and the technical scope of the present invention should not be construed to be limited by these. That is, the present invention can be embodied in various forms without departing from its technical concept or main features.

The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in the computer of the system or apparatus reads and executes the program. It can also be realized by processing to It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.

101 Substrate 121 First Electrode 123 Photoelectric Conversion Layer 123a First Part 123b Second Part

Claims (21)

a substrate;
a plurality of first electrodes spaced apart from each other on the substrate;
a photoelectric conversion layer including a first portion disposed on the plurality of first electrodes and a second portion disposed on the gap;
has
A semiconductor device, wherein a molar content of oxygen per unit volume in the second portion is higher than a molar content of oxygen per unit volume in the first portion. The semiconductor device according to claim 1, wherein the photoelectric conversion layer includes quantum dots. 3. The semiconductor device according to claim 2, wherein the quantum dots contain PbS. _4. The semiconductor device according to claim 3, wherein said second portion includes at least one of _PbSO2 , _PbSO3 and PbSO4. The semiconductor device according to claim 1, wherein the photoelectric conversion layer contains an organic photoelectric conversion material. The molar content of oxygen per unit volume in the second portion is at least 1.5 times the molar content of oxygen per unit volume in the first portion. 6. The semiconductor device according to any one of Items 1 to 5. further comprising a second electrode disposed on the photoelectric conversion layer;
The plurality of first electrodes are arranged along the main surface of the substrate,
In the second portion, the oxygen content is higher the closer to the second electrode in the direction perpendicular to the main surface of the substrate, and closer to the plurality of first electrodes in the direction perpendicular to the main surface of the substrate. 7. The semiconductor device according to any one of claims 1 to 6, wherein: the second portion has a highly oxidized portion and a less oxidized portion;
the content of oxygen per unit volume in the highly oxidized portion on a molar basis is higher than the content of oxygen per unit volume in the first portion on a molar basis;
the oxygen content on a molar basis per unit volume in the low oxidation portion is lower than the oxygen content on a molar basis per unit volume in the high oxidation portion;
The existence ratio of the highly oxidized portion in the second portion is higher in a direction perpendicular to the main surface of the substrate as it approaches the second electrode and lower as it approaches the plurality of first electrodes. 8. The semiconductor device according to claim 7. The molar content of oxygen per unit volume in the highly oxidized portion is higher in the direction perpendicular to the main surface of the substrate as it approaches the second electrode and lower as it approaches the plurality of first electrodes. 9. The semiconductor device according to claim 8, wherein: the second portion has a highly oxidized portion in which the content of oxygen per unit volume on a molar basis is higher than the content of oxygen per unit volume in the first portion on a molar basis;
The molar content of oxygen per unit volume in the highly oxidized portion is higher in the direction perpendicular to the main surface of the substrate as it approaches the second electrode and lower as it approaches the plurality of first electrodes. 8. The semiconductor device according to claim 7, wherein: a third electrode disposed between each of the plurality of first electrodes;
a first transistor connected to the third electrode;
further having
The semiconductor device according to any one of claims 1 to 10, wherein carriers accumulated in the photoelectric conversion layer are discharged from the third electrode by turning on the first transistor. further comprising a second transistor connected to one of the plurality of first electrodes;
12. The semiconductor device according to claim 11, wherein a period during which said first transistor is turned on and a period during which said second transistor is turned on overlap at least partially. A semiconductor device according to any one of claims 1 to 12;
an optical system for guiding incident light to the semiconductor device;
A photoelectric conversion device comprising: the main body;
13. The semiconductor device according to any one of claims 1 to 12, wherein the semiconductor device is provided in the body;
moving means for moving the body;
A moving body characterized by having preparing a substrate;
forming a plurality of spaced-apart first electrodes on the substrate;
forming a photoelectric conversion layer including a first portion overlying the plurality of first electrodes and a second portion overlying the gap;
irradiating the photoelectric conversion layer with light in an atmosphere containing oxygen;
has
A method of manufacturing a semiconductor device, wherein the second portion is irradiated with a larger amount of light than the first portion. 16. The method of manufacturing a semiconductor device according to claim 15, further comprising, before the step of irradiating the light, placing a mask for shielding the light irradiated onto the first portion. 16. The semiconductor according to claim 15, further comprising, before the step of irradiating the light, forming a sacrificial film on the first portion for absorbing the light with which the photoelectric conversion layer is irradiated. Method of manufacturing the device. 18. The method of manufacturing a semiconductor device according to claim 17, wherein the sacrificial film contains photoresist. The method further comprises forming a second electrode on the photoelectric conversion layer and etching the second electrode using the sacrificial film as a mask before the step of irradiating light. 19. A method of manufacturing a semiconductor device according to Item 17 or 18. 20. The method according to any one of claims 15 to 19, wherein in the step of irradiating light, the focus of the light irradiated onto the photoelectric conversion layer is above the upper surface of the photoelectric conversion layer. A method of manufacturing a semiconductor device. 21. The semiconductor according to any one of claims 15 to 20, wherein the molar content of oxygen in the second portion is higher than the molar content of oxygen in the first portion. Method of manufacturing the device.

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