# US 12,218,275 B2 · Semiconductor template and fabrication method

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- Number: US 12,218,275 B2
- Document ID: US12218275B2
- Status: Granted
- Kind: B2
- Application number: 17/436,818
- Filed: 2020-03-18
- Published: 2022-08-04
- Granted: 2025-02-04
- Earliest claimed: 2019-03-18
- Assignees: Hexagem AB
- Applicants: Hexagem AB
- Inventors: Zhaoxia Bi; Jonas Ohlsson; Lars Samuelson
- Web page: https://patentgrep.com/patent/US12218275B2

## CPC

- H10H 20/821: of the light-emitting regions, e.g. non-planar junctions
- H10P 14/3216: {Nitrides}
- H10H 20/01335: {the light-emitting regions comprising nitride materials}
- H10H 20/812: within the light-emitting regions, e.g. having quantum confinement structures
- H10H 20/825: containing nitrogen, e.g. GaN
- H10P 14/24: using chemical vapour deposition [CVD]
- H10P 14/271: {characterised by the preparation of substrate for selective deposition}
- H10P 14/2905: {Silicon, silicon germanium or germanium}
- H10P 14/2921: {being crystalline insulating materials}
- H10P 14/3256: {Microstructure}
- H10P 14/3258: {Crystal orientation}
- H10P 14/3416: {Nitrides}
- H10P 14/3466: {Crystal orientation}
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A method for fabrication of an InGaN semiconductor template, comprising growing an InGaN pyramid having inclined facets on a semiconductor substrate; processing the pyramid by removing semiconductor material to form a truncated pyramid having a first upper surface; growing InGaN, over the first upper surface, to form an InGaN template layer having a c-plane crystal facet forming a top surface. The InGaN semiconductor template is suitable for further fabrication of semiconductor devices, such as microLEDs configured to emit red, green or blue light.

## Claims

### Claim 1

A method for fabrication of an InGaN semiconductor template, comprising:
growing an InGaN pyramid having inclined facets on a semiconductor substrate;
processing the pyramid by removing semiconductor material to form a truncated pyramid having a first upper surface;
growing InGaN, over the first upper surface, to form an InGaN template layer having a c- plane crystal facet forming a top surface; and
depositing a coating layer on the pyramid, prior to removing semiconductor material;
wherein the processing comprises:
polishing the thus coated pyramid to form the truncated pyramid, and
etching the truncated pyramid to remove remaining coating material.

### Claim 2 (depends on 1)

The method of claim 1, wherein the step of polishing comprises chemical mechanical polishing.

### Claim 3 (depends on 1)

The method of claim 1, wherein the first upper surface is non-uniform, and wherein the growing of InGaN over the first upper surface provides flattening of the truncated pyramid.

### Claim 4

A method for fabrication of an InGaN semiconductor template, comprising:
growing an InGaN pyramid having inclined facets on a semiconductor substrate;
processing the pyramid by removing semiconductor material to form a truncated pyramid having a first upper surface; and
growing InGaN, over the first upper surface, to form an InGaN template layer having a c- plane crystal facet forming a top surface;
wherein the step of processing the pyramid comprises etching the pyramid;
wherein the etching is performed by in-situ annealing.

### Claim 5 (depends on 4)

The method of claim 4, further comprising:
growing an intermediate InGaN layer comprising a plurality of epitaxial layers directly onto the onto the first upper surface, to form a second upper surface; and
growing InGaN onto the second upper surface to form said InGaN template layer.

### Claim 6 (depends on 5)

The method of claim 5, wherein the intermediate InGaN layer is grown with an Indium content of >0% and <5%.

### Claim 7 (depends on 4)

The method of claim 4, wherein the InGaN template layer is grown with an Indium content of 5-20%.

### Claim 8 (depends on 4)

The method of claim 4, wherein the InGaN pyramid and the InGaN template layer are grown with the same relative Indium content, within a predetermined tolerance level.

### Claim 9 (depends on 4)

The method of claim 4, wherein growing an InGaN pyramid comprises epitaxially growing InGaN on a dislocation-free GaN seed structure provided in a mask opening on the semiconductor substrate.

### Claim 10 (depends on 9)

The method of claim 9, wherein said mask opening has a width in the range of 60-200 nm.

### Claim 11 (depends on 4)

A method for fabricating a semiconductor device, comprising:
fabricating an InGaN semiconductor template according to claim 4; and
growing additional semiconductor layers on the template layer to form a heterostructure, wherein at least one of said additional semiconductor layers has a different composition than said template layer.

### Claim 12 (depends on 11)

The method of claim 11, wherein the semiconductor device is a green light LED, and wherein at least one of said additional layers is grown with an Indium content of 20-30%.

### Claim 13 (depends on 11)

The method of claim 11, wherein the semiconductor device is a red light LED, and wherein at least one of said additional layers is grown with an Indium content of >35%.