Patent ID: 8368159

Claim:
An avalanche photodiode (APD) comprising: a first semiconductor substrate having a first doping type; a first semiconductor layer on top of the first semiconductor substrate, wherein the first semiconductor layer is doped with the first doping type; a second epitaxial layer on top of the first semiconductor layer, wherein the second epitaxial layer is in-situ doped with the first doping type at a concentration higher than a concentration of the first doping type in the first semiconductor layer; a third epitaxial layer on top of the second epitaxial layer, wherein the third epitaxial layer is in-situ doped with a second doping type, wherein the doping of the third epitaxial region forms a first p-n junction with the doping of the second epitaxial layer, wherein a carrier multiplication region includes the first p-n junction, and wherein the third epitaxial layer forms an absorption region for photons; and a first implanted region within the third epitaxial layer, wherein the implanted region is doped with the second doping type.