Light receiving element, image capturing element including the light receiving element and image capturing apparatus including the image capturing element

Abstract

A light receiving element includes a surface recombination prevention layer composed of a first compound semiconductor on which light is incident; a photoelectric conversion layer composed of a second compound semiconductor; and a compound semiconductor layer composed of a third compound semiconductor, the surface recombination prevention layer having a thickness of 30 nm or less. Also, there are provided an image capturing element including the light receiving element, and an image capturing apparatus including the image capturing element.

The invention is claimed as follows: 
     
         1 . A light receiving element, comprising:
 a surface recombination prevention layer composed of a first compound semiconductor on which light is incident;   a photoelectric conversion layer composed of a second compound semiconductor; and   a compound semiconductor layer composed of a third compound semiconductor, the surface recombination prevention layer having a thickness of 30 nm or less.   
     
     
         2 . The light receiving element according to  claim 1 , wherein
 the surface recombination prevention layer comprises InP, InGaAsP or AlInAs,   the photoelectric conversion layer comprises InGaAs, and   the compound semiconductor layer comprises InP, InGaAsP or AlInAs.   
     
     
         3 . The light receiving element according to  claim 1 , wherein
 the first compound semiconductor is an n type compound semiconductor,   the second compound semiconductor is an i type compound semiconductor, and   the third compound semiconductor is a p type compound semiconductor.   
     
     
         4 . The light receiving element according to  claim 1 , wherein
 when a band gap of the first compound semiconductor is represented by BG1, a band gap of the second compound semiconductor is represented by BG2, and a band gap of the third compound semiconductor is represented by BG3, the BG1, BG2 and BG3 satisfy BG1>BG2 and BG3>BG2.   
     
     
         5 . The light receiving element according to  claim 1 , wherein
 a transparent conductive material layer is formed on a light incident surface of the surface recombination prevention layer.   
     
     
         6 . The light receiving element according to  claim 5 , wherein
 the transparent conductive material layer comprises ITO, ITiO or NiO.   
     
     
         7 . A light receiving element, comprising:
 a transparent conductive material layer on which light is incident;   a surface recombination prevention layer composed of a first compound semiconductor;   a photoelectric conversion layer composed of a second compound semiconductor; and   a compound semiconductor layer composed of a third compound semiconductor, further including:   a contact layer composed of a fourth compound semiconductor formed between the transparent conductive material layer and the surface recombination prevention layer, the surface recombination prevention layer having a thickness of 30 nm or less, and the contact layer having a thickness of 20 nm or less.   
     
     
         8 . The light receiving element according to  claim 7 , wherein
 the contact layer comprises InGaAs, InP or InGaAsP, the surface recombination prevention layer comprises InP, InGaAsP or AlInAs,   the photoelectric conversion layer comprises InGaAs, and   the compound semiconductor layer comprises InGaAs, InP or InGaAsP.   
     
     
         9 . The light receiving element according to  claim 8 , wherein
 a combination of (the compound semiconductor of the contact layer and the compound semiconductor of the surface recombination prevention layer) can include (InGaAs, InP), (InGaAs, InGaAsP), (InGaAs, AlInAs), (InP, InGaAsP), (InP, AlInAs), (InGaAsP, InP), (InGaAsP, AlInAs) or (InXGaAsP, InYGaAsP)[where X>Y].   
     
     
         10 . The light receiving element according to  claim 7 , wherein
 the first compound semiconductor is an n type compound semiconductor,   the second compound semiconductor is an i type compound semiconductor,   the third compound semiconductor is a p type compound semiconductor, and   the fourth compound semiconductor is an n type compound semiconductor.   
     
     
         11 . The light receiving element according to  claim 7 , wherein
 when a band gap of the first compound semiconductor is represented by BG1, a band gap of the second compound semiconductor is represented by BG2, a band gap of the third compound semiconductor is represented by BG3, a band gap of the fourth compound semiconductor is represented by BG4, BG1, BG2, BG3 and BG4 satisfy BG1>BG2, BG3 22  BG2 and BG1>BG4.   
     
     
         12 . The light receiving element according to  claim 7 , wherein
 the transparent conductive material layer comprises ITO, ITiO or NiO.   
     
     
         13 . An image capturing element, comprising a light receiving element and a filter for passing light having a desirable wavelength disposed at a light incident side of the light receiving element, wherein the light receiving element includes
 a surface recombination prevention layer composed of a first compound semiconductor on which light is incident;   a photoelectric conversion layer composed of a second compound semiconductor; and   a compound semiconductor layer composed of a third compound semiconductor, the surface recombination prevention layer having a thickness of 30 nm or less.   
     
     
         14 . An image capturing element, comprising a light receiving element and a filter for passing light having a desirable wavelength disposed at a light incident side of the light receiving element, wherein the light receiving element includes
 a transparent conductive material layer on which light is incident;   a surface recombination prevention layer composed of a first compound semiconductor;   a photoelectric conversion layer composed of a second compound semiconductor; and   a compound semiconductor layer composed of a third compound semiconductor, further including:   a contact layer composed of a fourth compound semiconductor formed between the transparent conductive material layer and the surface recombination prevention layer, the surface recombination prevention layer having a thickness of 30 nm or less, and the contact layer having a thickness of 20 nm or less.   
     
     
         15 . An image capturing apparatus, comprising:
 a plurality of image capturing elements including light receiving elements and filters for passing light having a desirable wavelength disposed at light incident sides of the light receiving elements, in which the light receiving element includes   a surface recombination prevention layer composed of a first compound semiconductor on which light is incident;   a photoelectric conversion layer composed of a second compound semiconductor; and   a compound semiconductor layer composed of a third compound semiconductor, the surface recombination prevention layer having a thickness of 30 nm or less.   
     
     
         16 . An image capturing apparatus, comprising:
 a plurality of image capturing elements including light receiving elements and filters for passing light having a desirable wavelength disposed at light incident sides of the light receiving elements, in which the light receiving element includes a transparent conductive material layer on which light is incident;   a surface recombination prevention layer composed of a first compound semiconductor;   a photoelectric conversion layer composed of a second compound semiconductor; and   a compound semiconductor layer composed of a third compound semiconductor, further including:   a contact layer composed of a fourth compound semiconductor formed between the transparent conductive material layer and the surface recombination prevention layer, the surface recombination prevention layer having a thickness of 30 nm or less, and the contact layer having a thickness of 20 nm or less.