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US 9,437,759 B2Granted
Germanium metal-contact-free near-IR photodetector
AssigneeCoriant Advanced Technology, LLC
InventorsThomas Baehr-Jones, Yi Zhang, Michael J. Hochberg, Ari Novack
Life of this patent
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Abstract
A Ge-on-Si photodetector constructed without doping or contacting Germanium by metal is described. Despite the simplified fabrication process, the device has responsivity of 1.24 A/W, corresponding to 99.2% quantum efficiency. Dark current is 40 nA at −4 V reverse bias. 3-dB bandwidth is 30 GHz.
Claims24
A germanium photodetector, comprising:
- a first doped semiconductor contact;
- a second doped semiconductor contact;
- and
- an intrinsic germanium body in electrical contact with said first doped semiconductor contact and in electrical contact with said second doped semiconductor contact, said first doped semiconductor contact and said second doped semiconductor contact disposed on a same side of said intrinsic germanium body, said intrinsic germanium body lacking direct mechanical contact with a metal contact;
- said first doped semiconductor contact and said second doped semiconductor contact in electrical communication with respective metal terminals configured to provide electrical signals generated in the germanium photodetector by absorption of electromagnetic radiation to circuitry external to the germanium photodetector.
2 more elements
A method of detecting electromagnetic radiation with a germanium photodetector, comprising:
- providing a germanium photodetector, comprising:
- a first doped semiconductor contact;
- a second doped semiconductor contact;
- and
- an intrinsic germanium body in electrical contact with said first doped semiconductor contact and in electrical contact with said second doped semiconductor contact, said first doped semiconductor contact and said second doped semiconductor contact disposed on a same side of said intrinsic germanium body, said intrinsic germanium body lacking direct mechanical contact with a metal contact
- said first doped semiconductor contact and said second doped semiconductor contact in electrical communication with respective metal terminals configured to provide electrical signals generated in the germanium photodetector by absorption of electromagnetic radiation to circuitry external to the germanium photodetector;
- receiving electromagnetic radiation by said germanium photodetector;
- generating electrical signals representative of an intensity of said electromagnetic radiation or representative of data encoded in said electromagnetic radiation;
- and
- performing at least one of displaying said electrical signals to a user and recording said electrical signals in a machine-readable memory in non-volatile form.
7 more elements
A method of fabricating a germanium photodetector, comprising:
- patterning a silicon wafer having a surface by lithography and etching to create waveguides on the surface;
- doping the silicon by implantation and annealing to form a p-type contact and an n-type contact in a layer at the surface of the silicon wafer;
- performing germanium epitaxy to provide an intrinsic germanium body having no deliberately added dopant in contact with the n-type contact and the p-type contact, the germanium body having a shape bounded by crystallographic facets oriented at an angle to the surface of the silicon wafer;
- and
- applying metallization to form contact terminals.
2 more elements
Dependencies are inferred from the claim text.