US 8,008,696 B2Granted

Band gap modulated optical sensor

AssigneeInternational Business Machines Corporation

InventorsKangguo Cheng, Toshiharu Furukawa, Robert Robison, William R. Tonti

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Abstract

A complementary metal-oxide-semiconductor (CMOS) optical sensor structure comprises a pixel containing a charge collection well of a same semiconductor material as a semiconductor layer in a semiconductor substrate and at least another pixel containing another charge collection well of a different semiconductor material than the material of the semiconductor layer. The charge collections wells have different band gaps, and consequently, generate charge carriers in response to light having different wavelengths. The CMOS sensor structure thus includes at least two pixels responding to light of different wavelengths, enabling wavelength-sensitive, or color-sensitive, capture of an optical data. Further, a design structure for the inventive complementary metal-oxide-semiconductor (CMOS) image sensor is also provided.

Claims13

Dependent claims

A semiconductor structure comprising:

a first photosensitive diode located in a semiconductor substrate and comprising a first charge collection well and a first semiconductor portion, wherein said first semiconductor portion abuts a bottom surface of said first charge collection well, comprises a first semiconductor material, and has a doping of a first conductivity type, wherein said first charge collection well comprises said first semiconductor material and has a doping of a second conductivity type, wherein said second conductivity type is the opposite of said first conductivity type;
and
a second photosensitive diode located in said semiconductor substrate and comprising a second charge collection well and a second semiconductor portion, wherein said second semiconductor portion abuts a bottom surface of said second charge collection well, comprises a second semiconductor material, and has a doping of said first conductivity type, wherein said second charge collection well comprises said second semiconductor material and has a doping of said second conductivity type, and wherein said second semiconductor material is different from said first semiconductor material.

Dependencies are inferred from the claim text.