Back-illuminated type solid-state imaging device

Abstract

A back-illuminated type solid-state imaging device is provided in which an electric field to collect a signal charge (an electron, a hole and the like, for example) is reliably generated to reduce a crosstalk. The back-illuminated type solid-state imaging device includes a structure 34 having a semiconductor film 33 on a semiconductor substrate 31 through an insulation film 32, in which a photoelectric conversion element PD that constitutes a pixel is formed in the semiconductor substrate 31, at least part of transistors 15, 16, and 19 that constitute the pixel is formed in the semiconductor film 33, and a rear surface electrode 51 to which a voltage is applied is formed on the rear surface side of the semiconductor substrate 31.

What is claimed is: 
     
         1 . A back-illuminated type solid-state imaging device comprising:
 a semiconductor layer on a front surface side of a semiconductor substrate with an insulation film between them;   a photoelectric conversion element that constitutes a pixel in said semiconductor substrate, the photoelectric conversion element including a charge accumulation portion, the charge accumulation portion includes a plurality of impurity regions and a high impurity region formed directly between the plurality of impurity regions;   at least part of transistors that constitute said pixel are included in said semiconductor film; and   a rear surface electrode on the rear surface side of said semiconductor substrate to which a negative voltage is applied, the rear surface electrode being transparent,   wherein,   a semiconductor layer of an opposite conduction type to the charge accumulation portion of said photoelectric conversion element is formed in a portion of the semiconductor substrate under said insulation film, and   a semiconductor layer of an opposite conduction type to a charge accumulation portion of said photoelectric conversion element is formed in the semiconductor substrate under said insulation film.   
     
     
         2 . The back-illuminated type solid-state imaging device according to  claim 1 , wherein:
 the semiconductor substrate is a high resistance substrate, and   the transistors include a reset transistor, an amplifier transistor, and a selector transistor.   
     
     
         3 . The back-illuminated type solid-state imaging device according to  claim 2 , wherein a source of the reset transistor is connected to the photoelectric conversion element. 
     
     
         4 . The back-illuminated type solid-state imaging device according to  claim 3 , wherein:
 the electrically floating semiconductor layer is connected between the photoelectric conversion element and the source of the reset transistor, and   the source of the reset transistor is connected to a gate of the amplifier transistor.   
     
     
         5 . The back-illuminated type solid-state imaging device according to  claim 4 , wherein
 a drain of the reset transistor is connected to a power wiring and   a gate of the reset transistor is connected to reset wiring through which a reset pulse is received.   
     
     
         6 . The back-illuminated type solid-state imaging device according to  claim 5 , wherein:
 a drain of the amplifier transistor is connected to the power wiring, and   a source of the amplifier transistor is connected to a drain of the selector transistor.   
     
     
         7 . The back-illuminated type solid-state imaging device according to  claim 6 , wherein:
 a selector wiring is connected to a gate of the selector transistor,   a source of the selector transistor is connected to a vertical signal line,   a gate of a load transistor is connected to the vertical signal line, and   a gate of the load transistor is connected to a load wiring.   
     
     
         8 . The back-illuminated type solid-state imaging device according to  claim 2 , wherein the reset transistor resets a signal charge of the electrically floating semiconductor layer by discharging the signal charge of the electrically floating semiconductor layer into power wiring. 
     
     
         9 . The back-illuminated type solid-state imaging device according to  claim 2 , wherein:
 source-drain regions of the reset transistor, the amplifier transistor, and   the selector transistor are of formed in the charge accumulation region, the charge accumulation region is of n-type.   
     
     
         10 . The back-illuminated type solid-state imaging device according to  claim 1 , wherein the semiconductor layer of the opposite conduction type is of p-type. 
     
     
         11 . The back-illuminated type solid-state imaging device according to  claim 9 , wherein:
 the p-type semiconductor layer has an impurity concentration of approximately 1018 cm-3, and   an impurity concentration of the high resistance substrate is between 1012 cm-3 and 1015 cm-3.   
     
     
         12 . The back-illuminated type solid-state imaging device according to  claim 1 , wherein the negative voltage is applied to generate a large electric field to collect photoelectrons into the charge accumulation portion.