Patent ID: 9748290
Date: 2017-08-29
CPC Classifications: H01L

Claim:
1. An image sensor device structure, comprising: a substrate; a transfer transistor formed on the substrate; a floating node formed in the substrate; and a photosensitive element formed in the substrate, wherein the transfer transistor is formed between the floating node and the photosensitive element, the photosensitive element comprises a first doping region with a lateral doping gradient, the first doping region has a doping portion directly below a gate electrode of the transfer transistor, and a width of the doping portion decreases from a top of the doping portion to a bottom of the doping portion, wherein the first doping region comprises; a first doping portion formed below the transfer transistor; a second doping portion formed adjacent to the first doping portion and further away from the transfer transistor than the first doping portion is; and a third doping portion formed adjacent to the second doping portion and further away from the transfer transistor than the second doping portion is, wherein the first doping portion, the second doping portion and the third doping portion have the same depth but different doping concentrations, and the first doping region has a doping concentration decreasing from the first doping portion to the second doping portion and further to the third doping portion; a well region formed in the substrate; and an isolation structure embedded in the well region, and the photosensitive element is formed in a region between the transfer transistor and the well region.