Patent ID: 7335958
Filing Date: 2008-02-26
Classification: H01L

Abstract:
1. A pixel cell comprising: a photo-conversion device; a sensing node; and a first transistor for gating charge from said photo-conversion device to said sensing node; said first transistor comprising a gate electrode having a length and a channel region under said gate electrode, said length of said gate electrode extending from said photo-conversion device to said sensing node, said length of said gate electrode being divided into a plurality of gate electrode regions, each gate electrode region extending from said photo-conversion device to said sensing node, wherein at least one said gate electrode region has a work-function greater than a work-function of n+ Si, and another said gate electrode region has a different work-function from that of said at least one gate electrode region, said channel region comprising respective portions below each gate electrode region, wherein a doping concentration of at least one portion of said channel region is determined in part by the work-function of the respective gate electrode region.