Lateral ge/si avalanche photodetector

An avalanche photodetector, comprising:

• a silicon device layer, comprising:
• a first electrical contact region including a p dopant,
• a germanium contact region,
• an avalanche region,
• a charge region including the p dopant at a lower level of doping than the first contact region, separating the absorption region from the avalanche region, and
• a second electrical contact region including an n dopant;
• a germanium body adjacent to the germanium contact region;
• a first electrical terminal in electrical communication with the first electrical contact region;
• and
• a second electrical terminal in electrical communication with the second electrical contact region;
• whereby electrons, generated in the germanium body, move into the germanium contact region and then to the avalanche region, while holes generated in the germanium body move to the second electrical contact region.

A method of fabricating an avalanche photodiode comprising:

• providing a semiconductor wafer including a silicon device layer;
• producing a first electrical contact region in the silicon device layer by depositing a p dopant therein;
• producing a charge region in the silicon device layer including the p dopant at a lower level of doping than the first contact region, producing a germanium contact region adjacent the first electrical contact region and the charge region;
• producing a second electrical contact region in the silicon device layer including an n dopant, producing an avalanche region adjacent the charge region and the second electrical contact region;
• depositing a germanium body in contact with the germanium contact region;
• applying a first electrical terminal in electrical communication with the first electrical contact region;
• and
• applying a second electrical terminal in electrical communication with the second electrical contact region.