Image sensor with doped transfer gate

A method for fabricating an image sensor, wherein the image sensor comprises a plurality of pixels each pixel including a photodetector, wherein the pixels are arranged such that two adjacent pixels share a common charge-to-voltage conversion region, the method comprising:

• forming a plurality of transfer gates over a surface of the substrate layer, wherein a transfer gate is disposed between a respective shared charge-to-voltage conversion region and each photodetector associated with the shared charge-to-voltage conversion region and the transfer gates associated with each shared charge-to-voltage conversion region are spaced apart a predetermined distance to form a conversion region gap;
• depositing a masking conformal dielectric layer over the image sensor, wherein the masking conformal dielectric layer is continuous and covers the plurality of transfer gates and each photodetector associated with the shared charge-to-voltage conversion region and fills each conversion region gap;
• etching the masking conformal dielectric layer to form sidewall spacers along an outside edge of each transfer gate, wherein a portion of the masking conformal dielectric layer remains in each conversion region gap and is disposed over the entire surface of the substrate layer in each conversion region gap;
• and
• implanting an implant region in the plurality of transfer gates and the masking conformal dielectric layer in each conversion region gap masks the implant so that each charge-to-voltage conversion region is substantially devoid of the implant region.