Method And System For Germanium-On-Silicon Photodetectors Without Germanium Layer Contacts

Patent metadata

Field	Value
Publication number	US-2016155884-A1
Application number	US-201514926916-A
Country	US
Kind code	A1
Filing date	Oct 29, 2015
Priority date	Dec 1, 2014
Publication date	Jun 2, 2016
Grant date	—

Abstract

Methods and systems for germanium-on-silicon photodetectors without germanium layer contacts are disclosed and may include, in a semiconductor die having a photodetector, where the photodetector includes an n-type silicon layer, a germanium layer, a p-type silicon layer, and a metal contact on each of the n-type silicon layer and the p-type silicon layer: receiving an optical signal, absorbing the optical signal in the germanium layer, generating an electrical signal from the absorbed optical signal, and communicating the electrical signal out of the photodetector via the n-type silicon layer and the p-type silicon layer. The photodetector may include a horizontal or vertical junction double heterostructure where the germanium layer is above the n-type and p-type silicon layers. An intrinsically-doped silicon layer may be below the germanium layer between the n-type silicon layer and the p-type silicon layer. A top portion of the germanium layer may be p-doped.

First claim

What is claimed is:

1 . A method for optical communication, the method comprising:
in a semiconductor die having a photodetector, the photodetector comprising an n-type silicon layer, a germanium layer, a p-type silicon layer, and a metal contact on each of the n-type silicon layer and the p-type silicon layer:
receiving an optical signal;
absorbing the optical signal in the germanium layer;
generating an electrical signal from the absorbed optical signal; and
communicating the electrical signal out of the photodetector via the n-type silicon layer and the p-type silicon layer.

2 . The method according to claim 1 , wherein the photodetector comprises a horizontal junction double heterostructure where the germanium layer is above the n-type silicon layer and the p-type silicon layer.

3 . The method according to claim 2 , wherein an intrinsically-doped silicon layer is below the germanium layer between the n-type silicon layer and the p-type silicon layer.

4 . The method according to claim 2 , wherein a portion of the germanium layer nearest the p-doped silicon layer is p-doped.

5 . The method according to claim 1 , wherein the photodetector comprises a vertical junction double heterostructure where the germanium layer is above a lower-doped n-type silicon layer.

6 . The method according to claim 5 , wherein the n-type silicon layer and the p-type silicon layers are on opposite sides of the lower-doped silicon layer below the germanium layer where the p-type silicon layer and the lower-doped n-type silicon layer are in contact with the germanium layer while the n-type silicon layer is not.

7 . The method according to claim 5 , wherein a top portion of the germanium layer is doped p-type.

8 . The method according to claim 1 , wherein the photodetector comprises a surface-illuminated double heterostructure photodetector.

9 . The method according to claim 8 , wherein the n-type silicon layer and the p-type silicon layer in the surface-illuminated double heterostructure photodetector comprise interdigitated fingers.

10 . The method according to claim 8 , wherein the n-type silicon layer and the p-type silicon layer in the surface-illuminated double heterostructure photodetector comprise ring-shaped structures at an outer edge of the surface-illuminated double heterostructure photodetector.

11 . A system for communication, the system comprising:
a semiconductor die having a photodetector, the photodetector comprising an n-type silicon layer, a germanium layer, a p-type silicon layer, and a metal contact on each of the n-type silicon layer and the p-type silicon layer, the photodetector being operable to:
receive an optical signal;
absorb the optical signal in the germanium layer;
generate an electrical signal from the absorbed optical signal; and
communicate the electrical signal out of the photodetector via the n-type silicon layer and the p-type silicon layer.

12 . The system according to claim 11 , wherein the photodetector comprises a horizontal junction double heterostructure where the germanium layer is above the n-type silicon layer and the p-type silicon layer.

13 . The system according to claim 12 , wherein an intrinsically-doped silicon layer is below the germanium layer between the n-type silicon layer and the p-type silicon layer.

14 . The system according to claim 12 , wherein a portion of the germanium layer nearest the p-doped silicon layer is p-doped.

15 . The system according to claim 11 , wherein the photodetector comprises a vertical junction double heterostructure where the germanium layer is above a lower-doped n-type silicon layer.

16 . The system according to claim 15 , wherein the n-type silicon layer and the p-type silicon layers are on opposite sides of the lower-doped silicon layer below the germanium layer where the p-type silicon layer and the lower-doped n-type silicon layer are in contact with the germanium layer while the n-type silicon layer is not.

17 . The system according to claim 15 , wherein a top portion of the germanium layer is doped p-type.

18 . The system according to claim 11 , wherein the photodetector comprises a surface-illuminated double heterostructure photodetector with the n-type silicon layer and the p-type silicon layer in the surface-illuminated double heterostructure photodetector comprising interdigitated fingers.

19 . The system according to claim 18 , wherein the photodetector comprises a surface-illuminated double heterostructure photodetector with the n-type silicon layer and the p-type silicon layer in the surface-illuminated double heterostructure photodetector comprising ring-shaped structures at an outer edge of the surface-illuminated double heterostructure photodetector.

20 . A system for communication, the system comprising:
a semiconductor die having a double heterostructure photodetector, the double heterostructure photodetector comprising an n-type silicon layer, a germanium layer with p-type doping in a portion of the germanium layer, a p-type silicon layer, and a metal contact on each of the n-type silicon layer and the p-type silicon layer, the double heterostructure photodetector being operable to:
receive an optical signal;
absorb the optical signal in the germanium layer;
generate an electrical signal from the absorbed optical signal; and
communicate the electrical signal out of the photodetector via the n-type silicon layer and the p-type silicon layer.

Assignees

• Luxtera Inc

Inventors

• Hon Kam-Yan
• Masini Gianlorenzo
• Sahni Subal

Classifications

• G02B6/4292

  the light guide being disconnectable from the opto-electronic element, e.g. mutually self aligning arrangements · CPC title

• H10F77/241

  comprising ring electrodes · CPC title

• H10F30/223

  the potential barrier being a PIN barrier · CPC title

• H10F30/222

  the potential barrier being a PN heterojunction · CPC title

• H10F30/221

  the potential barrier being a PN homojunction · CPC title