阅读说明：本技术 光电转换元件和成像装置 (Photoelectric conversion element and imaging device ) 是由 坂东雅史 塩见治典 于 2019-01-17 设计创作，主要内容包括：一个实施方案的光电转换器设置有：第一电极,其由相互独立的多个电极构成；第二电极,其与所述第一电极相对；n型光电转换层,其包含半导体纳米粒子并且设置在所述第一电极和所述第二电极之间；以及半导体层,其包含氧化物半导体材料并且设置在所述第一电极和所述n型光电转换层之间。(A photoelectric converter of one embodiment is provided with: a first electrode composed of a plurality of electrodes independent of each other; a second electrode opposite to the first electrode; an n-type photoelectric conversion layer containing semiconductor nanoparticles and disposed between the first electrode and the second electrode; and a semiconductor layer including an oxide semiconductor material and disposed between the first electrode and the n-type photoelectric conversion layer.)

1. A photoelectric conversion element comprising:

a first electrode composed of a plurality of electrodes independent of each other;

a second electrode arranged opposite to the first electrode;

an n-type photoelectric conversion layer containing semiconductor nanoparticles, the n-type photoelectric conversion layer being disposed between the first electrode and the second electrode; and

a semiconductor layer including an oxide semiconductor material, the semiconductor layer being disposed between the first electrode and the n-type photoelectric conversion layer.

2. The photoelectric conversion element according to claim 1, wherein the n-type photoelectric conversion layer has 3 × 10¹⁶cm^-3Above and 1 × 10¹⁸cm^-3The following carrier densities.

3. The photoelectric conversion element according to claim 1, wherein the semiconductor layer has 1 × 10¹⁷cm^-3The following carrier densities.

4. The photoelectric conversion element according to claim 1, wherein

The semiconductor nanoparticles include a core and a ligand bound to a surface of the core, and

the core comprises PbS, PbSe, PbTe and CuInSe₂、ZnCuInSe、CuInS₂、HgTe、InAs、InSb、Ag₂At least one of S and CuZnSnSSe.

5. The photoelectric conversion element according to claim 1, wherein

The semiconductor nanoparticles include a core and a ligand bound to a surface of the core, and

the ligand includes any one of a chlorine atom, a bromine atom and an iodine atom.

6. The photoelectric conversion element according to claim 4, wherein

The semiconductor nanoparticle further includes a shell disposed about the core, and

the shell comprises PbO and PbO₂、Pb₃O₄At least one of ZnS, ZnSe and ZnTe.

7. The photoelectric conversion element according to claim 1, wherein the semiconductor layer comprises IGZO, ZTO, Zn₂SnO₄、InGaZnSnO、GTO、Ga₂O₃:SnO₂And IGO.

8. The photoelectric conversion element according to claim 1, wherein

The first electrode is formed by using any one of titanium (Ti), silver (Ag), aluminum (Al), magnesium (Mg), chromium (Cr), nickel (Ni), tungsten (W), and copper (Cu), and

the second electrode is formed by using Indium Tin Oxide (ITO).

9. The photoelectric conversion element according to claim 1, comprising

An insulating layer between the first electrode and the semiconductor layer, wherein

The first electrode includes a charge readout electrode electrically connected to the n-type photoelectric conversion layer via an opening provided in the insulating layer, and a charge accumulation electrode arranged opposite to the n-type photoelectric conversion layer with the insulating layer interposed therebetween.

10. The photoelectric conversion element according to claim 9, wherein the first electrode comprises a charge transfer electrode between the charge readout electrode and the charge accumulation electrode.

11. The photoelectric conversion element according to claim 1, wherein respective voltages are applied to the plurality of electrodes constituting the first electrode, respectively.

12. The photoelectric conversion element according to claim 1, further comprising

A semiconductor substrate of

The first electrode, the semiconductor layer, the n-type photoelectric conversion layer, and the second electrode are provided in this order on a first surface side of the semiconductor substrate.

13. The photoelectric conversion element according to claim 12, wherein the semiconductor substrate comprises a drive circuit, and the plurality of electrodes constituting the first electrode are respectively connected to the drive circuit.

14. The photoelectric conversion element according to claim 12, wherein a multilayer wiring layer is formed on a second surface side opposite to the first surface of the semiconductor substrate.

15. An image forming apparatus includes

A plurality of pixels each provided with one or more photoelectric conversion elements,

the one or more photoelectric conversion elements each include

A first electrode composed of a plurality of electrodes independent of each other,

a second electrode disposed opposite to the first electrode,

an n-type photoelectric conversion layer containing semiconductor nanoparticles, the n-type photoelectric conversion layer being disposed between the first electrode and the second electrode, and

a semiconductor layer including an oxide semiconductor material, the semiconductor layer being disposed between the first electrode and the n-type photoelectric conversion layer.

Technical Field

For example, the present disclosure relates to a photoelectric conversion element having a photoelectric conversion layer containing semiconductor nanoparticles, and an imaging device containing the photoelectric conversion element.

Background

The pixel size of an imaging Device such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor has been decreasing. An imaging device including a photoelectric conversion portion outside a semiconductor substrate generally accumulates charges generated by photoelectric conversion in a floating diffusion layer (floating diffusion: FD) formed inside the semiconductor substrate.

Incidentally, an imaging device provided with a photoelectric conversion portion inside a semiconductor substrate temporarily accumulates charges generated by photoelectric conversion in the photoelectric conversion portion inside the semiconductor substrate, and then transfers the charges to the FD. This makes it possible to completely deplete the photoelectric conversion portion. In contrast, the electric charges generated by the photoelectric conversion portion provided outside the semiconductor substrate are directly accumulated in the FD as described above, and thus it is difficult to completely deplete the photoelectric conversion portion. This increases kTC noise and causes more unfavorable random noise, so that the imaging quality deteriorates.

To solve this problem, PTL 1, for example, discloses an imaging element provided with an electrode for charge accumulation. The electrode for charge accumulation is provided on a first electrode side of the first electrode and a second electrode spaced apart from the first electrode, and is opposed to the photoelectric conversion layer with the insulating layer interposed therebetween. The first electrode and the second electrode are disposed so as to oppose each other with the photoelectric conversion layer interposed therebetween. The first electrode is disposed on a side opposite to the light incident side. The imaging element can accumulate charges generated by photoelectric conversion in the photoelectric conversion layer, and can completely deplete the charge accumulation section when exposure is started. Therefore, image quality deterioration can be reduced.

Reference list

Patent document

PTL 1: japanese unexamined patent application publication No. 2017-157816

PTL 2: japanese unexamined patent application publication No. 2010-177392

Disclosure of Invention

Incidentally, for example, as a photoelectric conversion element having sensitivity to near-infrared light developed in recent years, PTL2 discloses a photoelectric conversion element in which semiconductor nanoparticles are used for a photoelectric conversion layer. A photoelectric conversion element having a photoelectric conversion layer formed therein by using semiconductor nanoparticles needs to improve quantum efficiency.

It is desirable to provide a photoelectric conversion element and an imaging device that make it possible to improve quantum efficiency.

The photoelectric conversion element according to the embodiment of the present disclosure includes: a first electrode composed of a plurality of electrodes independent of each other; a second electrode arranged opposite to the first electrode; an n-type photoelectric conversion layer containing semiconductor nanoparticles, the n-type photoelectric conversion layer being disposed between the first electrode and the second electrode; and a semiconductor layer containing an oxide semiconductor material, the semiconductor layer being provided between the first electrode and the n-type photoelectric conversion layer.

An imaging device according to an embodiment of the present disclosure includes a plurality of pixels each provided with one or more photoelectric conversion elements, and the photoelectric conversion elements are the photoelectric conversion elements according to the above-described embodiments.

In the photoelectric conversion element and the imaging device according to the respective embodiments of the present disclosure, on the semiconductor layer provided between the first electrode and the second electrode arranged opposite to each other, the n-type photoelectric conversion layer containing the semiconductor nanoparticles is provided as the photoelectric conversion layer. This suppresses recombination of charges, which are generated by photoelectric conversion, by applying a strong electric field to the n-type photoelectric conversion layer.

According to the photoelectric conversion element and the imaging device of the respective embodiments of the present disclosure, the n-type photoelectric conversion layer containing the semiconductor nanoparticles is provided as the photoelectric conversion layer, which makes it possible to apply a strong electric field to the n-type photoelectric conversion layer laminated on the semiconductor layer. Therefore, recombination of charges in the photoelectric conversion layer can be suppressed, and quantum efficiency can be improved.

It is to be noted that the above-described effects are not necessarily restrictive. Any one of the effects described in the present specification or other effects that can be grasped from the present specification can be achieved simultaneously with or instead of the above-described effects.

Drawings

Fig. 1 is a schematic cross-sectional view of an imaging member according to an embodiment of the present disclosure.

Fig. 2 is a schematic cross-sectional view of the photoelectric conversion element shown in fig. 1.

Fig. 3 is an equivalent circuit diagram of the imaging element shown in fig. 1.

Fig. 4 is a schematic diagram showing a configuration of a lower electrode of the imaging element shown in fig. 1 and a transistor included in the control portion.

Fig. 5A is a diagram describing the operation principle of the photoelectric conversion element shown in fig. 1.

Fig. 5B is a diagram describing the operation principle of the photoelectric conversion element shown in fig. 1.

Fig. 5C is a diagram describing the operation principle of the photoelectric conversion element shown in fig. 1.

Fig. 6A is a schematic cross-sectional view for describing a manufacturing method of the imaging element shown in fig. 1.

Fig. 6B is a schematic cross-sectional view showing a step subsequent to fig. 6A.

Fig. 6C is a schematic cross-sectional view showing a step subsequent to fig. 6B.

Fig. 6D is a schematic cross-sectional view showing a step subsequent to fig. 6C.

Fig. 6E is a schematic cross-sectional view showing a step subsequent to fig. 6D.

Fig. 7 is a timing chart showing an operation example of the photoelectric conversion element shown in fig. 1.

Fig. 8 is a potential distribution diagram between electrodes when the photoelectric conversion element serving as the comparative example is irradiated with light.

Fig. 9 is a potential distribution diagram between electrodes when the photoelectric conversion element shown in fig. 1 is irradiated with light.

Fig. 10 is a block diagram showing a configuration of an imaging apparatus including the imaging element shown in fig. 1 as a pixel.

Fig. 11 is a functional block diagram showing an example of an electronic device (camera) including the imaging apparatus shown in fig. 10.

Fig. 12 is a block diagram showing a schematic configuration example of the in-vivo information acquisition system.

Fig. 13 is a diagram showing a schematic configuration example of an endoscopic surgery system.

Fig. 14 is a block diagram showing a functional configuration example of a camera head and a Camera Control Unit (CCU).

Fig. 15 is a block diagram showing a schematic configuration example of the vehicle control system.

Fig. 16 is an auxiliary explanatory view of an example of the mounting positions of the vehicle exterior information detecting portion and the imaging portion.

Fig. 17 is a characteristic diagram showing a relationship between the doping concentration and the quantum efficiency of the photoelectric conversion layer according to the embodiment.

Detailed Description

Hereinafter, some embodiments of the present disclosure are described in detail with reference to the accompanying drawings. Note that the description is made in the following order.

1. Embodiment (example of photoelectric conversion element provided with n-type photoelectric conversion layer)

1-1. arrangement of imaging elements

1-2. method for producing imaging element

1-3. method for controlling image forming element

1-4. action and Effect

2. Application example