Method and system for optoelectronic receivers utilizing waveguide heterojunction phototransistors integrated in a CMOS SOI wafer

A system for processing signals, the system comprising:

• a photonically-enabled CMOS chip fabricated in a silicon-on-insulator substrate, said photonically-enabled CMOS chip being operable to:
• receive one or more optical signals via a top surface of said photonically-enabled CMOS chip;
• and
• generate one or more electrical signals in said photonically-enabled CMOS chip utilizing one or more germanium waveguide heterojunction phototransistors that detect said one or more optical signals;
• wherein said one or more germanium waveguide heterojunction phototransistors comprise a base and a split collector, said split collector comprising a silicon-on-insulator (SOI) layer and a germanium layer, wherein the thickness of the germanium layer is such that carriers in the base do not interact with defects from an interface between the silicon SOI layer and the germanium layer.

A semiconductor device, the device comprising:

• a germanium phototransistor on a photonically-enabled CMOS chip, said germanium phototransistor comprising:
• a base;
• a polycrystalline emitter;
• and
• a split collector comprising a germanium layer and a silicon-on-insulator (SOI) layer, said split collector being coupled to a collector electrode, said coupling utilizing a shallow trench, a collector contact tub, and a salicided collector contact.