Patent ID: 8048705

Claim:
A method of forming a CMOS image sensor device, the method comprising: providing a semiconductor substrate having a P-type impurity characteristic including a surface region; forming a first silicon dioxide overlying the surface region; forming an N-type impurity region in a vicinity underlying a first region of the first silicon dioxide to cause formation of a photo diode device characterized by the N-type impurity region and the P-type impurity; depositing a mask layer covering the first region of the first silicon dioxide; removing a portion of the first silicon dioxide that is not covered by the mask layer; removing the mask layer; forming a first thickness of silicon dioxide in the first region and a second thickness of silicon dioxide in the portion that was not covered by the mask layer; and forming a first gate structure overlying a second region of the second thickness of silicon dioxide; wherein the first thickness of the silicon dioxide prevents a surface damage on the first region of the surface region that is caused by a subsequent plasma etch process in order to reduce a dark current of the photo diode device.