CMOS image sensor and method of fabrication
AssigneeMicron Technology, Inc.
InventorSungkwon (Chris) Hong
Life of this patent
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Abstract
A CMOS imaging device including a two pixel detection system for red, green, and blue light. One pixel detects red and blue light and another pixel detects green light. The detection of red and blue is based on wavelength and the device is structured such that in the red/blue pixel, detection of blue light is at a shallow substrate depth, while detection of red is at a deeper substrate depth. The pixel array is structured such that the red/blue pixel is adjacent to the green pixel and alternates between red/blue and green pixels. The invention is also related to methods of forming such an imager array and pixels.
Claims30
A method for forming a pixel sensor cell consisting of two color sensors, said method comprising:
- forming a first color component photoconversion device within a substrate, and below the surface of said substrate at a first depth corresponding to an optimal absorption depth for a first wavelength of light;
- and
- forming a second color component photoconversion device within said substrate at a second depth corresponding to an optimal absorption depth for a second wavelength of light;
- wherein said first color component photoconversion device is formed in said substrate over said second color component photoconversion device such that the first color component photoconversion device is located closer to an upper surface of the substrate than the second color component photoconversion device, said first and second color component photoconversion devices being spaced apart vertically by a region of said substrate which does not produce photogenerated charges.
A method for forming an array of pixel sensor cells comprising:
- forming a plurality of first and second pixels on a substrate wherein said plurality of first and second pixels are arranged into an array of rows and columns;
- forming a first color component photoconversion device in said first pixels below an upper surface of said substrate at a first depth, said first depth corresponding to an optimal absorption depth for a first wavelength of light;
- forming a second color component photoconversion device in said first pixels below the upper surface of said substrate at a second depth, said second depth corresponding to an optimal absorption depth for a second wavelength of light, wherein said first color component photoconversion device is formed over said second color component photoconversion device within said substrate such that the first color component photoconversion device is located closer to the upper surface of the substrate than the second color component photoconversion device, said first and second color component photo conversion devices being separated by a region of said substrate which does not produce photogenerated charges;
- and
- forming said second pixels as third color component photoconversion devices, said second pixels being configured to produce photogenerated charges in response to a third wavelength of light;
- and
- wherein said first and second pixels are arranged in an alternating pattern in said array.
Dependencies are inferred from the claim text.