Solid-state imaging element and imaging apparatus

Abstract

Provided is a solid-state imaging element that includes a photoelectric conversion layer of a first electrical conductivity type including a plurality of pixel regions, an electrode electrically coupled to the photoelectric conversion layer and provided for each of the pixel regions, a semiconductor layer provided between the electrode and the photoelectric conversion layer and having a bandgap larger than a bandgap of the photoelectric conversion layer, a diffusion part disposed in a vicinity of an edge of the pixel region and including an impurity of a second electrical conductivity type that is diffused from the semiconductor layer across the photoelectric conversion layer, and a non-diffusion part provided inside the diffusion part and not including the impurity of the second electrical conductivity type in the photoelectric conversion layer.

1 . A solid-state imaging element, comprising:
 a photoelectric conversion layer of a first electrical conductivity type, wherein the photoelectric conversion layer includes a plurality of pixel regions;   an electrode for each pixel region of the plurality of pixel regions, wherein the electrode is electrically coupled to the photoelectric conversion layer;   a semiconductor layer between the electrode and the photoelectric conversion layer, wherein the semiconductor layer has a bandgap larger than a bandgap of the photoelectric conversion layer;   a plurality of diffusion parts in each pixel region of the plurality of pixel regions, wherein
 each diffusion part of the plurality of diffusion parts includes an impurity, of a second electrical conductivity type, that is diffused into the photoelectric conversion layer from the semiconductor layer, 
 the plurality of diffusion parts includes a first diffusion part and a set of second diffusion parts, 
 the first diffusion part is in a middle part of each pixel region of the plurality of pixel regions, and 
 the set of second diffusion parts is in a vicinity of an edge of each pixel region of the plurality of pixel regions; and 
   a non-diffusion part in each pixel region of the plurality of pixel regions, wherein the non-diffusion part separates the first diffusion part from the set of second diffusion parts.   
     
     
         2 . The solid-state imaging element according to  claim 1 , wherein in the non-diffusion part, an impurity concentration of the impurity of the second electrical conductivity type is zero in each of the photoelectric conversion layer and the semiconductor layer. 
     
     
         3 . The solid-state imaging element according to  claim 1 , wherein the first diffusion part has a density lower than a density of each second diffusion part of the set of second diffusion parts. 
     
     
         4 . The solid-state imaging element according to  claim 1 , wherein
 each pixel region of the plurality of pixel regions includes:
 a first interface between the photoelectric conversion layer and each diffusion part of the plurality of diffusion parts, and 
 a second interface between the semiconductor layer and each diffusion part of the plurality of diffusion parts, and 
   an area of the first interface is smaller than an area of the second interface.   
     
     
         5 . The solid-state imaging element according to  claim 1 , wherein a shape of each diffusion part of the plurality of diffusion parts corresponds to a circular planar shape. 
     
     
         6 . The solid-state imaging element according to  claim 1 , wherein a shape of each diffusion part of the plurality of diffusion parts corresponds to a quadrangular shape. 
     
     
         7 . The solid-state imaging element according to  claim 1 , further comprising a cap layer in the non-diffusion part, wherein the cap layer is between the semiconductor layer and the electrode. 
     
     
         8 . The solid-state imaging element according to  claim 7 , wherein the cap layer includes a group III-V semiconductor compound. 
     
     
         9 . The solid-state imaging element according to  claim 1 , wherein the photoelectric conversion layer includes a group III-V semiconductor compound. 
     
     
         10 . The solid-state imaging element according to  claim 9 , wherein the group III-V semiconductor compound includes one of indium phosphide, indium gallium arsenide, gallium arsenide antimonide, gallium antimonide, indium arsenide, indium antimonide, indium gallium arsenide phosphide, or indium gallium aluminum arsenide. 
     
     
         11 . The solid-state imaging element according to  claim 1 , wherein the semiconductor layer includes a group III-V semiconductor compound. 
     
     
         12 . The solid-state imaging element according to  claim 11 , wherein the group III-V semiconductor compound includes one of indium gallium arsenide, gallium arsenide antimonide, indium gallium arsenide phosphide, indium gallium aluminum arsenide, indium phosphide, indium aluminum arsenide, indium aluminum arsenide antimonide, or aluminum arsenide antimonide. 
     
     
         13 . An imaging apparatus, comprising:
 a solid-state imaging element, wherein the solid-state imaging element includes:
 a photoelectric conversion layer of a first electrical conductivity type, wherein the photoelectric conversion layer includes a plurality of pixel regions; 
 an electrode for each pixel region of the plurality of pixel regions, wherein the electrode is electrically coupled to the photoelectric conversion layer; 
 a semiconductor layer between the electrode and the photoelectric conversion layer, wherein the semiconductor layer has a bandgap larger than a bandgap of the photoelectric conversion layer; 
 a plurality of diffusion parts in each pixel region of the plurality of pixel regions, wherein
 each diffusion part of the plurality of diffusion parts includes an impurity, of a second electrical conductivity type, that is diffused into the photoelectric conversion layer from the semiconductor layer, 
 the plurality of diffusion parts includes a first diffusion part and a set of second diffusion parts, 
 the first diffusion part is in a middle part of each pixel region of the plurality of pixel regions, and 
 the set of second diffusion parts is in a vicinity of an edge of each pixel region of the plurality of pixel regions; and 
 
 a non-diffusion part in each pixel region of the plurality of pixel regions, wherein the non-diffusion part separates the first diffusion part from the set of second diffusion parts.