Semiconductor photodiode device with isolation region

Abstract

A dielectrically isolated photodiode having an increased p-n junction size with improved photo-carrier collection efficiency. The photodiode comprises a first layer of semiconductor material formed on the bottom and the walls of an isolation region; a second layer of semiconductor material formed on the first layer. The second layer forming a first p-n junction with the first layer and having opposite conductivity type compared to that of the first layer. The photodiode also comprises a third layer of semiconductor material formed on the second layer and electrically coupled to the first layer. The third layer having the same conductivity type as the first layer and forming a second p-n junction with the second layer. During operation, the first p-n junction functions to collect photo-generated carriers that extend to the bottom and walls of the isolation region, thereby increasing the active collecting p-n junction area per isolation region area to improve efficiency of the photodiode.

Dependencies are inferred from the claim text.