Photoelectric conversion element and method for manufacturing same

Abstract

A photoelectric conversion element includes a first semiconductor layer that exhibits a first conductivity type and is provided in a selective area over a substrate, a second semiconductor layer that exhibits a second conductivity type and is disposed opposed to the first semiconductor layer, and a third semiconductor layer that is provided between the first and second semiconductor layers and exhibits a substantially intrinsic conductivity type. The third semiconductor layer has at least one corner part that is not in contact with the first semiconductor layer.

What is claimed is: 
     
         1 . A method for manufacturing a photoelectric conversion element, the method comprising:
 forming a first semiconductor layer exhibiting a first conductivity type in a selective area over a substrate;   forming a third semiconductor layer on the first semiconductor layer, the third semiconductor layer having at least one corner part that is not in contact with the first semiconductor layer and exhibiting a substantially intrinsic conductivity type; and   forming a second semiconductor layer exhibiting a second conductivity type on the third semiconductor layer.   
     
     
         2 . The method for manufacturing a photoelectric conversion element according to  claim 1 , the method further comprising
 forming an interlayer insulating film having a through-hole opposed to the first semiconductor layer over the substrate after the first semiconductor layer is formed and before the third semiconductor layer is formed,   wherein   in the forming a third semiconductor layer, the third semiconductor layer is so formed as to be extended from an inside of the through-hole to a top surface of the interlayer insulating film.   
     
     
         3 . The method for manufacturing a photoelectric conversion element according to  claim 2 , wherein
 in the forming an interlayer insulating film, the through-hole is formed by a one-step etching process so that a wall surface of the through-hole be a flat surface.   
     
     
         4 . The method for manufacturing a photoelectric conversion element according to  claim 2 , wherein
 the through-hole is so formed that an opening of the through-hole on a side of the substrate surrounds an outside of a forming area of the first semiconductor layer in a direction along a substrate surface.   
     
     
         5 . The method for manufacturing a photoelectric conversion element according to  claim 2 , wherein
 in the forming an interlayer insulating film, the through-hole is formed by a two-step or more-step etching process so that shape of a wall surface of the through-hole be a staircase shape.   
     
     
         6 . The method for manufacturing a photoelectric conversion element according to  claim 5 , wherein
 the through-hole is so formed that at least one step part of a plurality of step parts in the staircase shape is larger than a step part closest to the substrate.   
     
     
         7 . The method for manufacturing a photoelectric conversion element according to  claim 1 , the method further comprising
 forming an interlayer insulating film having a through-hole opposed to the first semiconductor layer over the substrate after the first semiconductor layer is formed and before the third semiconductor layer is formed,   wherein   in the forming a third semiconductor layer, the third semiconductor layer is so formed in the through-hole of the interlayer insulating film as to be separated from a wall surface of the through-hole.