# US 10,312,397 B2 · Avalanche photodiode with low breakdown voltage

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- Number: US 10,312,397 B2
- Document ID: US10312397B2
- Status: Granted
- Kind: B2
- Application number: 15/442,512
- Filed: 2017-02-24
- Published: 2017-09-07
- Granted: 2019-06-04
- Earliest claimed: 2017-02-24
- Assignees: Intel Corporation
- Applicants: Intel Corporation
- Inventors: Yimin Kang; Han-Din Liu
- Web page: https://patentgrep.com/patent/US10312397B2

## CPC

- H10F 30/2255: {in which the active layers form heterostructures, e.g. SAM structures}
- G02B 6/42: Coupling light guides with opto-electronic elements
- H10F 77/959: {for devices working in avalanche mode}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

An Si/Ge SACM avalanche photodiodes (APD) having low breakdown voltage characteristics includes an absorption region and a multiplication region having various layers of particular thicknesses and doping concentrations. An optical waveguide can guide infrared and/or optical signals or energy into the absorption region. The resulting photo-generated carriers are swept into the i-Si layer and/or multiplication region for avalanche multiplication. The APD has a breakdown bias voltage of well less than 12 V and an operating bandwidth of greater than 10 GHz, and is therefore suitable for use in consumer electronic devices, high speed communication networks, and the like.

## Claims

### Claim 1

A semiconductor avalanche photodiode (APD), comprising:
a first region of n-type doped silicon;
a second region disposed directly above the first region, the second region being of silicon, and wherein a thickness of the second region is between about 0.07 micrometers and about 0.13 micrometers;
a third region disposed directly above the second region, the third region being of p-type doped silicon; and
a fourth region disposed directly above the third region, separated from the second region by the third region, and further separated from the first region by the second region and the third region, the fourth region being of germanium, wherein a surface of the fourth region completely overlaps with a portion of a surface of the third region, and a remaining portion of the surface of the third region is free from the surface of the fourth region.

### Claim 2 (depends on 1)

The APD of claim 1, further comprising:
a substrate, wherein the first region, the second region, the third region, and the fourth region are formed on the substrate.

### Claim 3 (depends on 1)

The APD of claim 1, further comprising:
a fifth region disposed on the fourth region, wherein the fifth region includes p-type doped material.

### Claim 4 (depends on 3)

The APD of claim 3, further comprising:
a metal contact disposed on the fifth region.

### Claim 5 (depends on 1)

The APD of claim 1, wherein the thickness of the second region is about 100 nanometers.

### Claim 6 (depends on 1)

The APD of claim 1, wherein the second region has a doping concentration of less than about 5×1015 centimeters−3 (cm−3).

### Claim 7 (depends on 1)

The APD of claim 1, wherein the third region has a doping concentration of between about 2×1018 centimeters−3 (cm−3) and about 3×1018 cm−3.

### Claim 8 (depends on 1)

The APD of claim 1, wherein the second region is doped differently than the first region and the third region.

### Claim 9 (depends on 1)

The APD of claim 1, wherein the APD is a group-IV APD.

### Claim 10 (depends on 1)

The APD of claim 1, wherein a thickness of the third region is about 20 nanometers, wherein the thickness of the third region is measured from a first surface of the third region adjacent to a surface of the fourth region to a second surface of the third region adjacent to a surface of the second region.

### Claim 11

A semiconductor avalanche photodiode (APD), comprising:
a first region of n-type doped silicon above a substrate;
a second region disposed directly above the first region and further above the substrate, the second region being of silicon, and wherein the second region has a doping concentration of less than about 5×1015 centimeter−3 (cm−3);
a third region disposed directly above the second region and further above the substrate, the third region being of p-type doped silicon, and wherein the third region has a doping concentration of between about 2×1018 cm−3 and about 3×1018 cm−3; and
a fourth region disposed directly above the third region and further above the substrate, separated from the second region by the third region, and further separated from the first region by the second region and the third region, the fourth region being of germanium.

### Claim 12 (depends on 11)

The APD of claim 11, wherein the second region has a thickness of between about 0.07 micrometers and about 0.13 micrometers.

### Claim 13 (depends on 12)

The APD of claim 12, wherein the thickness of the second region is about 100 nanometers.

### Claim 14 (depends on 11)

The APD of claim 11, further comprising:
a substrate, wherein the first region, the second region, the third region, and the fourth region are formed on the substrate.

### Claim 15 (depends on 11)

The APD of claim 11, wherein the third region has a thickness of about 20 nanometers, wherein the thickness of the third region is measured from a first surface of the third region adjacent to a surface of the fourth region to a second surface of the third region adjacent to a surface of the second region.

### Claim 16 (depends on 11)

The APD of claim 11, further comprising:
a fifth region disposed on the fourth region, wherein the fifth region includes p-type doped material.

### Claim 17 (depends on 16)

The APD of claim 16, further comprising:
a metal contact disposed on the fifth region.

### Claim 18 (depends on 17)

The APD of claim 17, wherein the metal contact is a first metal contact, and wherein the APD further comprises:
a second metal contact disposed on the first region.

### Claim 19 (depends on 11)

The APD of claim 11, wherein the second region is doped differently than the first region and the third region.