Omnivision Technologies, Inc.

Chih-huei Wu

Xinping James He

Tiemin Zhao

Hongli Yang

The active pixel includes a photodiode, a transfer gate, and a reset transistor. The photodiode is substantially covered with an overlying structure, thus protecting the entire surface of the photodiode from damage. This substantially eliminates potential leakage current sources, which result in dark current. In one embodiment, the photodiode is covered by a FOX region in combination with the transfer gate.

Active pixel having reduced dark current in a CMOS image sensor

The active pixel includes a photodiode, a reset transistor, and a pixel output transistor. The photodiode is substantially covered with a protective structure, thus protecting the entire surface of the photodiode from damage. This substantially eliminates potential leakage current sources, which result in dark current. The protective structure has a photodiode contact formed therein to electrically connect the photodiode to the pixel output transistor.

A method for protecting an image sensor die is disclosed. The method comprises forming a plurality of image sensor die having micro-lenses onto a semiconductor wafer. Then, a protective layer is formed over the image sensor die. After the protective layer has been formed, and without any removal step of the protective layer, the wafer is diced to separate the plurality of image sensor die. Finally, the image sensor die are mounted onto an integrated circuit package and the protective layer is removed.

Sacrificial protective layer for image sensors and method of using

A method for reducing dark current in a photodiode is disclosed. The photodiode comprises a N-well formed in a P-substrate. The method comprises doping the surface of said N-well with a nitrogen dopant. Alternatively, an oxygen or silicon dopant may be used. Still alternatively, a silicon oxynitride layer may be formed over the N-well.

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Sunnyvale, CA, United States of America

Chih-huei Wu