Patent ID: 7888266

Claim:
A method of forming a semiconductor structure comprising: providing a semiconductor substrate including a semiconductor layer comprising a first semiconductor material and having a doping of a first conductivity type; forming a first photosensitive diode in said semiconductor substrate, wherein said first photosensitive diode comprises a first charge collection well and a first semiconductor portion that is a portion of said semiconductor layer, wherein said first semiconductor portion is formed directly underneath said first charge collection well, comprises said first semiconductor material, and has a doping of said 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 forming a second photosensitive diode in said semiconductor substrate, wherein said second photosensitive diode comprises a second charge collection well and a second semiconductor portion, wherein said second semiconductor portion is formed directly underneath said second charge collection well, comprises a second semiconductor material having a different composition than said first semiconductor material, has a doping of said first conductivity type, and contacts said first semiconductor material in said semiconductor layer, wherein said second charge collection well comprises said second semiconductor material and has a doping of said second conductivity type.