CMOS image sensor with high full-well-capacity
AssigneeOmniVision Technologies, Inc.
InventorsDuli Mao, Hsin-Chih Tai, Vincent Venezia, Yin Qian, Howard E. Rhodes
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Abstract
An image sensor with a high full-well capacity includes a photosensitive region, a transfer gate, and sidewall spacers. The photosensitive region is formed to accumulate an image charge in response to light. The transfer gate disposed adjacent to the photosensitive region and coupled to selectively transfer the image charge from the photosensitive region to other pixel circuitry. First and second sidewall spacers are disposed on either side of the transfer gate. The first sidewall spacer closest to the photosensitive region is narrower than the second sidewall spacer. In some cases, the first sidewall spacer may be omitted.
Claims11
A method of fabricating a complementary metal-oxide semiconductor (“CMOS”) image sensor (“CIS”), comprising:
- forming a photosensitive region and a transistor gate adjacent to the photosensitive region;
- forming first and second sidewall spacers adjacent to the transistor gate, wherein the first sidewall spacer is narrower than the second sidewall spacer;
- and
- forming a pinning layer over the photosensitive region after forming the first and second sidewall spacers and after the first sidewall spacer is made narrower than the second sidewall spacer.
A method of fabricating a complementary metal-oxide semiconductor (“CMOS”) image sensor (“CIS”), comprising:
- forming a photosensitive region and a transistor gate adjacent to the photosensitive region;
- forming first and second sidewall spacers adjacent to the transistor gate, wherein the first sidewall spacer is narrower than the second sidewall spacer;
- forming a pinning layer over the photosensitive region after forming the first and second sidewall spacers;
- and
- forming an oxide over the photosensitive region prior to forming the pinning layer,
- wherein the pinning layer is implanted into an interface between the oxide and the photosensitive region after forming the sidewall spacers.
Dependencies are inferred from the claim text.