Photoelectric conversion device method for producing photoelectric conversion device and image pickup system

Abstract

A photoelectric conversion device includes a photoelectric conversion region having a plurality of photoelectric conversion elements and a first MOS transistor configured to read a signal in response to an electric charge of each photoelectric conversion element; and a peripheral circuit region having a second MOS transistor configured to drive the first MOS transistor and/or amplify the signal read from the photoelectric conversion region, the photoelectric conversion region and the peripheral circuit region being located on the same semiconductor substrate, wherein an impurity concentration in a drain of the first MOS transistor is lower than an impurity concentration in a drain of the second MOS transistor.

1 - 9 . (canceled) 
     
     
         10 . A method for manufacturing a photoelectric conversion device that includes a pixel region having a plurality of photoelectric conversion elements and first MOS transistors each configured to read a signal in response to an electric charge of a respective photoelectric conversion element, and a peripheral circuit region having second MOS transistors configured to drive the first MOS transistors and/or amplify signals read from the pixel region, the pixel region and the peripheral circuit region being located on a same semiconductor substrate, the method comprising steps of:
 forming gate electrodes of the first and second MOS transistors;   implanting impurity ions of a first conductivity type by using the gate electrodes as masks;   forming an insulating film that covers the peripheral circuit region and an entirety of the pixel region;   removing the insulating film formed on the peripheral circuit region using an etch back procedure while protecting the insulating film formed on the pixel region using a mask, such that side spacers of the second MOS transistors are formed; and   implanting impurity ions of the first conductivity type by using the insulating film on the pixel region and the side spacers as masks.   
     
     
         11 . The method for manufacturing a photoelectric conversion device according to  claim 10 , further comprising steps of:
 forming a second insulating film that covers an entirety of the photoelectric conversion region and the peripheral circuit region;   forming contact holes in a region corresponding to a drain region of the second insulating film; and   implanting impurity ions of the first conductivity type into the contact holes in a self-aligned manner.