US 7,397,101 B1Granted

Germanium silicon heterostructure photodetectors

AssigneeLuxtera, Inc.

InventorsGianlorenzo Masini, Lawrence C. Gunn, III, Giovanni Capellini

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Abstract

A horizontal germanium silicon heterostructure photodetector comprising a horizontal germanium p-i-n diode disposed over a horizontal parasitic silicon p-i-n diode uses silicon contacts for electrically coupling to the germanium p-i-n through the p-type doped and n-type doped regions in the silicon p-i-n without requiring direct physical contact to germanium material. The current invention may be optically coupled to on-chip and/or off-chip optical waveguide through end-fire or evanescent coupling. In some cases, the doping of the germanium p-type doped and/or n-type doped region may be accomplished based on out-diffusion of dopants in the doped silicon material of the underlying parasitic silicon p-i-n during high temperature steps in the fabrication process such as, the germanium deposition step(s), cyclic annealing, contact annealing and/or dopant activation.

Claims15

Dependent claims

A horizontal germanium silicon photodetector integrated on a substrate comprising:

a horizontal silicon pin (positive-intrinsic-negative) diode disposed on a substrate comprising:
a first positive region comprising p-type doped silicon;
a first intrinsic region comprising silicon;
and,
a first negative region comprising n-type doped silicon;
a horizontal germanium pin diode disposed on top of the horizontal silicon pin diode comprising:
a second positive region comprising p-type doped germanium substantially aligned with the first positive region;
a second intrinsic region comprising germanium substantially aligned with the first intrinsic region;
and,
a second negative region comprising n-type doped germanium substantially aligned with the first negative region;
an anode contact coupled to the first positive region for establishing electrical contact to both the first positive region and to the second positive region through the first positive region;
and,
a cathode contact coupled to the first negative region for establishing electrical contact to the first negative region and to the second negative region through the first negative region, thereby establishing a germanium on silicon photodetector with silicon contacts.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/177,132Filed 7 Jul 2005 · us provisional application
Priority: 8 Jul 2004
Granted: 8 Jul 2008
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

H10F 77/122
Active materials: comprising only Group IV materials
G02B 6/4295
Coupling light guides with opto-electronic elements: coupling with semiconductor devices activated by light through the light guide, e.g.…
H10F 30/223
The devices having only one potential barrier, e.g. photodiodes: the potential barrier being a PIN barrier
H10F 30/2255
The potential barrier working in avalanche mode, e.g. avalanche photodiodes: in which the active layers form heterostructures, e.g. SAM structures