CIS image sensors with epitaxy layers and methods for forming the same

摘要

A method includes performing a first epitaxy to grow a first epitaxy layer of a first conductivity type, and performing a second epitaxy to grow a second epitaxy layer of a second conductivity type opposite the first conductivity type over the first epitaxy layer. The first and the second epitaxy layers form a diode. The method further includes forming a gate dielectric over the first epitaxy layer, forming a gate electrode over the gate dielectric, and implanting a top portion of the first epitaxy layer and the second epitaxy layer to form a source/drain region adjacent to the gate dielectric.

主权项

1. A device comprising:
a photo diode comprising:
a first semiconductor layer of a first conductivity type; anda second semiconductor layer over the first semiconductor layer and of a second conductivity type opposite to the first conductivity type; a silicon germanium layer of the second conductivity type underlying the first semiconductor layer; a gate dielectric over the second semiconductor layer; a gate electrode over the gate dielectric; and a source/drain region of the first conductivity type, wherein the source/drain region, the gate dielectric, and the gate electrode form portions of a transistor, and the transistor is configured to turn on and turn off an electrical connection between the photo diode and the source/drain region.