Anode up—cathode down silicon and germanium photodiode

A photodiode comprising:

• an N type silicon region formed in a silicon substrate, said N type silicon region being a cathode of said photodiode;
• a P type germanium region situated over said N type silicon region, said P type germanium region being an anode of said photodiode;
• a dielectric layer situated over said N type silicon region, said dielectric layer having an anode window, said P type germanium region situated within said anode window;
• a P type silicon cap over said P type germanium region;
• an anode contact of said photodiode being situated on said P type silicon cap.

A photodiode comprising:

• an N type silicon region formed in a top silicon layer in a silicon-on-insulator (SOI) device, said N type silicon region being a cathode of said photodiode;
• a P type germanium region situated over said N type silicon region, said P type germanium region being an anode of said photodiode;
• a dielectric layer situated over said N type silicon region, said dielectric layer having an anode window, said P type germanium region situated within said anode window;
• a P type silicon cap over said P type germanium region;
• an anode contact of said photodiode being situated on said P type silicon cap;
• wherein said anode contact situated on said P type silicon cap is a silicided contact.

A photodiode comprising:

• an N type silicon region formed in a bulk silicon substrate in a bulk silicon device, said N type silicon region being a cathode of said photodiode;
• a P type germanium region situated over said N type silicon region, said P type germanium region being an anode of said photodiode;
• a dielectric layer situated over said N type silicon region, said dielectric layer having an anode window, said P type germanium region situated within said anode window;
• a P type silicon cap over said P type germanium region;
• wherein a cathode contact of said photodiode situated on said N type silicon region is a silicided contact.