Patent ID: 7776676

Claim:
A method of fabricating a complementary metal-oxide-semiconductor (CMOS) image sensor, comprising: providing a substrate having a photo sensitive region and a transistor device region of the CMOS image sensor; forming a p type well in the substrate of the transistor device region; sequentially forming a dielectric layer and an un-doped polysilicon layer on the substrate; doping the un-doped polysilicon layer to form an n type polysilicon layer on a first portion of the transistor device region and a p type polysilicon layer on the photo sensitive region and on a second portion of the transistor device region; after the step of doping the un-doped polysilicon layer, patterning the dielectric layer, the n type polysilicon layer and the p type polysilicon layer to form a plurality of n type gate structures and a p type gate structure on the p type well of the transistor device region of the CMOS image sensor, wherein the p type gate structure is the gate structure of one of a transfer transistor, a reset transistor, a source coupling transistor and a select transistor; and forming a photo sensitive diode in the substrate of the photo sensitive region.