Patent ID: 8039916

Claim:
A CMOS active pixel sensor including: a semiconductor body of a first conductivity type; four photocollectors each including a blue detector region of a second conductivity type opposite to that of the first conductivity type and having a first doping concentration, the detector regions each disposed below a separate detector pinning region of the first conductivity type disposed on the surface of the semiconductor body, an edge of each detector region extending beyond an edge of the detector pinning region with which it is associated, the detector regions disposed proximate to four corners of a layout square; a common node formed from a region of a second conductivity type and having a second doping concentration at least equal in magnitude to the first doping concentration and disposed in the semiconductor body below a common-node pinning region of the first conductivity type disposed on the surface of the semiconductor body, first edges of the region of the second conductivity type forming the common node extending beyond a first edge of the common-node pinning region of each detector region and spaced apart from each detector region to form a select channel for each detector region, and second edges of the region of the second conductivity type extending beyond second edge of the common-node pinning region opposite the first edge in each one of the four detector regions; a polysilicon color-select gate for each photocollector, each color-select gate overlying and insulated from its select channel and color-select gate coupled to a blue color-select signal line; a sense node formed by a reset-transistor source region of the second conductivity type disposed in the semiconductor body and having a third doping concentration at least equal in magnitude to the second doping concentration, the second edge of the region of the second conductivity type forming the common node underlying and in electrical contact with the reset-transistor source region, the sense node disposed between a first one and a second one of the blue detectors; a reset-transistor drain region of the second conductivity type disposed in the semiconductor body and spaced apart from the reset-transistor source region to form a reset transistor channel, the reset-transistor drain region coupled to a power-supply node; a polysilicon reset-transistor gate overlying and insulated from the reset-transistor channel, the reset-transistor gate coupled to a reset-signal line; and a source-follower transistor having a gate coupled to the sense node, a drain coupled to a power-supply node, and a source forming a pixel-sensor output.