Avalanche photodiode and an optical receiver having the same

Patent metadata

Field	Value
Publication number	US-2022271186-A1
Application number	US-202117249192-A
Country	US
Kind code	A1
Filing date	Feb 23, 2021
Priority date	Feb 23, 2021
Publication date	Aug 25, 2022
Grant date	—

Abstract

Examples described herein relate to an avalanche photodiode (APD) and an optical receiver including the APD. The APD may include a substrate and a photon absorption region disposed on the substrate. The substrate may include a charge carrier acceleration region under the photon absorption region; a charge region adjacent to the charge carrier acceleration region; and a charge carrier multiplication region adjacent to the charge region. The charge carrier acceleration region, the charge region, and the charge carrier multiplication region are laterally formed in the substrate. When a biasing voltage is applied to the optoelectronic device, photon-generated free charge carriers may be generated in the photon absorption region and are diffused into the charge carrier acceleration region. The charge carrier acceleration region is configured to accelerate the photon-generated free charge carriers prior to the photon-generated free charge carriers entering into the charge region and undergoing impact ionization in the charge carrier multiplication region.

First claim

1 . An avalanche photodiode (APD) comprising:
a substrate comprising semiconductor material; and a photon absorption region disposed on the substrate, the substrate comprising:
a charge carrier acceleration region under the photon absorption region;
a charge region adjacent to the charge carrier acceleration region;
a charge carrier multiplication region adjacent to the charge region, wherein the charge carrier acceleration region, the charge region, and the charge carrier multiplication region are laterally formed in the substrate;
a first contact region adjacent to the charge carrier acceleration region and comprising a first-type doping; and a second contact region adjacent to the charge carrier multiplication region and comprising a second-type doping, wherein the charge region comprises either the first-type doping or the second-type doping, and wherein a boundary of the charge region and a boundary of the second contact region that are oriented toward each other are shorter than respective opposite boundaries of the charge region and the second contact region.

2 . The APD of claim 1 , wherein when a biasing voltage is applied to the APD, photon-generated free charge carriers are generated in the photon absorption region and are diffused into the charge carrier acceleration region, and wherein the charge carrier acceleration region is configured to accelerate the photon-generated free charge carriers prior to the photon-generated free charge carriers entering into the charge region and undergoing impact ionization in the charge carrier multiplication region.

3 . (canceled)

4 . The APD of claim 1 , wherein the first-type doping is a p-type doping and the second-type doping is an n-type doping.

5 . The APD of claim 1 , wherein the first-type doping is an n-type doping and the second-type doping is a p-type doping.

6 . (canceled)

7 . The APD of claim 2 , wherein, under the application of the biasing voltage, an electric field across the charge carrier multiplication region is higher than an electric field across the charge carrier acceleration region.

8 . The APD of claim 1 , wherein the substrate comprises a first semiconductor material and the photon absorption region comprises a second semiconductor material different from the first semiconductor material.

9 . The APD of claim 8 , wherein the first semiconductor material comprises one of Silicon (Si), Indium phosphide (InP), Indium aluminum arsenide (InAlAs), or Aluminum gallium arsenide (AlGaAs), and wherein the second semiconductor material comprises one of Indium gallium arsenide (InGaAs), Germanium (Ge), or Gallium arsenide (GaAs), or Silicon (Si).

10 . The APD of claim 8 , wherein the first semiconductor material has a wider energy bandgap in comparison to an energy bandgap of the second semiconductor material so that under application of a biasing voltage, there exists a non-zero electric field across the charge carrier acceleration region.

11 . The APD of claim 1 , wherein the charge carrier acceleration region and the charge carrier multiplication region are un-doped.

12 . An optical receiver comprising:
an avalanche photodiode (APD) to convert an incoming optical signal into an analog current, the APD comprising:
a substrate comprising semiconductor material; and
a photon absorption region disposed on the substrate, the substrate comprising:
a charge carrier acceleration region under the photon absorption region;
a charge region adjacent to the charge carrier acceleration region;
a charge carrier multiplication region adjacent to the charge region, wherein the charge carrier acceleration region, the charge region, and the charge carrier multiplication region are laterally formed in the substrate;
a first contact region adjacent to the charge carrier acceleration region and comprising a first-type doping; and
a second contact region adjacent to the charge carrier multiplication region and comprising a second-type doping, wherein the charge region comprises either the first-type doping or the second-type doping, and wherein a boundary of the charge region and a boundary of the second contact region that are oriented toward each other are shorter than respective opposite boundaries of the charge region and the second contact region; and
an analog front-end (AFE) coupled to the APD to receive the analog current generated by the APD.

13 . The optical receiver of claim 12 , wherein when a biasing voltage is applied to the APD, photon-generated free charge carriers are generated in the photon absorption region and are diffused into the charge carrier acceleration region, and wherein the charge carrier acceleration region is configured to accelerate the photon-generated free charge carriers prior to the photon-generated free charge carriers entering into the charge region and undergoing impact ionization in the charge carrier multiplication region.

14 - 15 . (canceled)

16 . The optical receiver of claim 13 , wherein, under the application of the biasing voltage, an electric field across the charge carrier multiplication region is higher than an electric field across the charge carrier acceleration region.

17 . The optical receiver of claim 12 , wherein the substrate comprises a first semiconductor material and the photon absorption region comprises a second semiconductor material different from the first semiconductor material.

18 . The optical receiver of claim 17 , wherein the first semiconductor material has a wider energy bandgap in comparison to an energy bandgap of the second semiconductor material.

19 . The optical receiver of claim 18 , wherein, under application of a biasing voltage, there exists a non-zero electric field across the charge carrier acceleration region.

20 . The optical receiver of claim 12 , wherein the charge carrier acceleration region and the charge carrier multiplication region are un-doped.

21 . The APD of claim 1 , wherein a thickness of the charge region is in a range from about 30 nm to 130 nm.

22 . The APD of claim 1 , wherein a thickness of the charge region is 70 nm.

23 . The optical receiver of claim 12 , wherein a thickness of the charge region is suitably selected to achieve an electric field distribution which can cause impact ionization to occur in the charge carrier multiplication region thereby reducing excess noise.

24 . The optical receiver of claim 12 , wherein a width of the charge carrier acceleration region is same as a width of the photon absorption region.

Assignees

• Hewlett Packard Entpr Dev Lp

Inventors

• Yuan Yuan
• Liang Di
• Zeng Xiaoge
• Huang Zhihong

Classifications

• H10F77/933

  for devices having potential barriers · CPC title

• H10F10/16

  Photovoltaic cells having only PN heterojunction potential barriers · CPC title

• H10F30/2255 Primary

  in which the active layers form heterostructures, e.g. SAM structures · CPC title

• H01L31/02005

  Electricity · mapped topic

• H01L31/1075 Primary

  Electricity · mapped topic