Patent ID: 8669133

Claim:
A method for fabricating an image sensor semiconductor device, comprising: providing a silicon substrate having a first type of dopant; forming, on the silicon substrate, a silicon layer of a second type of dopant different from the first type of dopant; forming a first well and a second well of the second type of dopant at a first depth in the silicon layer, the first and second wells being spaced horizontally a distance from each other to define a region of the silicon layer therebetween; and forming an image sensor in the region of the silicon layer, wherein the image sensor comprises a photodiode that includes: a first doped layer of the first type of dopant at a second depth, the first doped layer contacting the silicon layer of the second type of dopant; and a second doped layer of the second type of dopant at a third depth, the second doped layer contacting the second well on a first side, and contacting the first doped layer on a second side and a third side, wherein the first depth is greater than the second depth and the second depth is greater than the third depth.