# US 2014/0151839 A1 · Avalanche photodiode with low breakdown voltage

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- Number: US 2014/0151839 A1
- Document ID: US20140151839A1
- Status: Published application
- Kind: A1
- Application number: 13/976,379
- Filed: 2011-12-29
- Published: 2014-06-05
- Earliest claimed: 2011-12-29
- Assignees: Intel Corporation
- Inventors: Yimin Kang; Han-Din Liu
- Web page: https://patentgrep.com/patent/US20140151839A1

## CPC

- H10H 20/81: Bodies
- H10F 30/2255: {in which the active layers form heterostructures, e.g. SAM structures}
- H10F 77/14: Shape of semiconductor bodies; Shapes, relative sizes or dispositions of semiconductor regions within semiconductor bodies
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

An Si/Ge SACM avalanche photo-diodes (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

An avalanche photodiode (APD), comprising:
a substrate;
an n-type doped silicon (n+ Si) layer disposed on the substrate;
an intrinsic silicon (i-Si) layer disposed on a portion of the n+ Si layer;
a p-type doped silicon (p Si) layer disposed on the i-Si layer;
an intrinsic germanium (i-Ge) layer disposed on a portion of the p Si layer; and
a p-type doped silicon (p+ Ge) layer disposed on the i-Ge layer,
wherein the thickness of the i-Si layer is between about 0.07 to 0.13 micrometers (μm).

### Claim 2 (depends on 1)

The APD of claim 1, wherein the thickness of the p Si layer is about 20 nanometers (nm).

### Claim 3 (depends on 1)

The APD of claim 1, wherein the thickness of the i-Si layer is about 100 nm.

### Claim 4 (depends on 1)

The APD of claim 1, wherein the doping concentration of the i-Si layer is less than 5×1015 cm−3.

### Claim 5 (depends on 1)

The APD of claim 1, wherein the doping concentration of the p Si layer is between about 2×1018 cm−3 to 3×1018 cm−3.

### Claim 6 (depends on 1)

The APD of claim 1, further comprising:
a passivation layer disposed on portions of the p+ Ge layer, the p Si layer, and the n+ Si layer;
a first metal contact disposed on the p+ Ge layer; and
a second metal contact disposed on the n+ Si layer.

### Claim 7 (depends on 1)

The APD of claim 1, having associated, therewith a breakdown bias, wherein the breakdown bias is less than 12 Volts (V).

### Claim 8 (depends on 7)

The APD of claim 7, wherein the breakdown bias is about 8.5 V.

### Claim 9 (depends on 1)

The APD of claim 1, having associated therewith an operating bandwidth, wherein the operating bandwidth is about 10 GHz.

### Claim 10 (depends on 1)

The APD of claim 1, further comprising:
a breakdown bias of about 8.5 V; and
an operating bandwidth of greater than 8 GHz.

### Claim 11 (depends on 10)

The APD of claim 10, wherein the operating bandwidth is greater than 10 GHz.

### Claim 12 (depends on 1)

The APD of claim 1, wherein the p+ Ge layer and the i-Ge layer form an absorption region.

### Claim 13 (depends on 12)

The APD of claim 12, further comprising a waveguide configured to guide optical energy into the absorption region.

### Claim 14 (depends on 1)

The APD of claim 1, wherein the p Si layer, the i-Si layer, and the n+ Si layer form a carrier multiplication region.

### Claim 15

An electronic device, comprising:
circuitry having a predefined operating voltage, the circuitry including an avalanche photodiode (APD), the APD including:
a substrate;
an n-type doped silicon (n+ Si) layer disposed on the substrate;
an intrinsic silicon (i-Si) layer disposed on a portion of the n+ Si layer;
a p-type doped silicon (p Si) layer disposed on the i-Si layer;
an intrinsic germanium (i-Ge) layer disposed on a portion of the p Si layer; and
a p-type doped silicon (p+ Ge) layer disposed on the i-Ge layer, wherein:
the thickness of the i-Si layer is between about 0.07 to 0.13 micrometers (μm); and
a breakdown bias of the APD is below the operating voltage of the circuitry.

### Claim 16 (depends on 15)

The electronic device of claim 15, wherein the predefined operating voltage of the circuitry is 12 V.

### Claim 17 (depends on 15)

The electronic device of claim 15, wherein the breakdown bias of the APD is about 8.5 V.

### Claim 18 (depends on 15)

The electronic device of claim 15, wherein the thickness of the p Si layer is about 20 nanometers (nm).

### Claim 19 (depends on 1)

The electronic device of claim 1, wherein the thickness of the i-Si layer is about 100 nm.

### Claim 20 (depends on 1)

The electronic device of claim 1, wherein the doping concentration of the i-Si layer is less than 5×1015 cm−3.

### Claim 21 (depends on 1)

The electronic device of claim 1, wherein the doping concentration of the p Si layer is between about 2×1018 cm−3 to 3×1018 cm−3.

### Claim 22

An avalanche photodiode (APD), comprising:
an intrinsic silicon (i-Si) layer having a thickness of between about 0.07 to 0.13 micrometers (μm) and a doping concentration of less than about 5×1015 cm−3; and
a p-type doped silicon (p Si) layer having a thickness of about 20 nm and a doping concentration of between about 2×1018 cm−3 to 3×1018 cm−3.

### Claim 23 (depends on 22)

The APD of claim 22, wherein the P Si layer is disposed on the i-Si layer.

### Claim 24 (depends on 22)

The APD of claim 22, wherein the i-Si layer has a thickness of about 100 nanometers (nm).