Patent ID: 7989252

Claim:
A method for fabricating a pixel cell of CMOS image sensor, comprising: preparing a semiconductor substrate divided into region I and region II; forming an insulation layer on the surface of the semiconductor substrate in the region I and a gate dielectric layer on the surface of the semiconductor substrate in the region II, wherein the insulation layer is thicker than the gate dielectric layer; forming a poly-silicon gate on the surface of the semiconductor substrate in the region II; forming a deep doped well in the region I through an ion implantation with high energy; performing an ion implantation with low energy in the region I and an ion implantation for lightly doped source/drain in the region II simultaneously, wherein the ion implantation with low energy and the ion implantation with high energy are different in conductive type, and wherein peak concentration of the ion implantation with low energy is in the insulation layer; and forming source/drain regions in the semiconductor substrate in the region II.