# US 8,541,315 B2 · High throughput epitaxial lift off for flexible electronics

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- Number: US 8,541,315 B2
- Document ID: US8541315B2
- Status: Granted
- Kind: B2
- Application number: 13/236,119
- Filed: 2011-09-19
- Published: 2013-03-21
- Granted: 2013-09-24
- Earliest claimed: 2011-09-19
- Assignees: International Business Machines Corporation
- Applicants: Cheng-Wei Cheng; Kuen-Ting Shiu
- Inventors: Cheng-Wei Cheng; Kuen-Ting Shiu
- Web page: https://patentgrep.com/patent/US8541315B2

## CPC

- H10P 50/642: {Chemical etching}
- H10P 50/646: {of Group III-V materials}
- H10P 95/112: {leaving a reusable substrate, e.g. epitaxial lift off}
- H10P 14/2905: {Silicon, silicon germanium or germanium}
- H10P 14/2907: {being Group IIIA-VA materials}
- H10P 14/3202: {Materials thereof}
- H10P 14/3218: {Phosphides}
- H10P 14/3248: {consisting of two layers}
- H10P 14/3402: {characterised by the chemical composition}
- H10P 14/38: {characterised by treatments done after the formation of the materials}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A method of removing a semiconductor device layer from an underlying base substrate is provided in which a sacrificial phosphide-containing layer is formed between a semiconductor device layer and a base substrate. In some embodiments, a semiconductor buffer layer can be formed on an upper surface of the base substrate prior to forming the sacrificial phosphide-buffer layer. The resultant structure is then etched utilizing a non-HF etchant to release the semiconductor device layer from the base semiconductor substrate. After releasing the semiconductor device layer from the base substrate, the base substrate can be re-used.

## Claims

### Claim 1

A method of releasing a semiconductor device layer from a base substrate, said method comprising:
forming a sacrificial phosphide-containing layer on an upper surface of a base substrate;
forming a first protection layer on an upper surface of the sacrificial phosphide-containing layer;
forming a semiconductor device layer on an upper surface of the first protection layer, wherein said semiconductor device layer is a same semiconductor material as the sacrificial phosphide-containing layer;
forming a second protection layer on an upper surface of the semiconductor device layer; and
removing the sacrificial phosphide-containing layer from between the semiconductor device layer and the base substrate, wherein said removing comprises etching with a non-HF containing etchant.

### Claim 2 (depends on 1)

The method of claim 1, wherein said base substrate is an III-V compound semiconductor material.

### Claim 3 (depends on 1)

The method of claim 1, wherein said base substrate is a Ge-containing semiconductor material.

### Claim 4 (depends on 3)

The method of claim 3, further comprising forming a semiconductor buffer layer between the Ge-containing semiconductor substrate and the sacrificial phosphide-containing layer.

### Claim 5 (depends on 3)

The method of claim 3, wherein said semiconductor buffer layer is an III-V compound semiconductor material.

### Claim 6 (depends on 1)

The method of claim 1, wherein said non-HF etchant is a non-HF containing acid.

### Claim 7 (depends on 6)

The method of claim 6, wherein said non-HF containing acid is selected from the group consisting of HCl, HBr, HI and mixtures thereof.

### Claim 8 (depends on 1)

The method of claim 1, wherein said removing the sacrificial phosphide-containing layer utilizing said non-HF containing etchant is performed at a temperature from room temperature up to, but not beyond a boiling point of the non-HF containing etchant.

### Claim 9 (depends on 1)

The method of claim 1, wherein after removing the sacrificial phosphide-containing layer from between the base substrate and the semiconductor device layer, said base substrate has a RMS surface roughness of from 0.1 nm to 0.5 nm or within ±0.5 nm of an initial RMS roughness.

### Claim 10 (depends on 1)

The method of claim 1, wherein said sacrificial phosphide-containing layer is composed of a compound of phosphorus and at least one element that is less electronegative than said phosphorus.

### Claim 11 (depends on 10)

The method of claim 10, wherein said sacrificial phosphide-containing layer comprises InAlP, InGaP, InAsP, GaAsP, InGaAlP, InGaAsP, GaP, InP and phosphide-containing alloys.

### Claim 12 (depends on 1)

The method of claim 1, wherein said sacrificial phosphide-containing layer is a different semiconductor material than said base substrate.

### Claim 13

A method of releasing a semiconductor device layer from a base substrate, said method comprising:
forming a semiconductor buffer layer on an upper surface of a base substrate;
forming a sacrificial phosphide-containing layer on an upper surface of the semiconductor buffer layer;
forming a first protection layer on an upper surface of the sacrificial phosphide-containing layer;
forming a semiconductor device layer on an upper surface of the first protection layer, wherein said semiconductor device layer is a same semiconductor material as the sacrificial phosphide-containing layer;
forming a second protection layer on an upper surface of the semiconductor device layer; and
removing the sacrificial phosphide-containing layer located between the semiconductor device layer and the base substrate, wherein said removing comprising etching with a non-HF containing etchant.

### Claim 14 (depends on 13)

The method of claim 13, further comprising removing the semiconductor buffer layer from atop the base substrate.

### Claim 15 (depends on 13)

The method of claim 13, wherein said base substrate is an III-V compound semiconductor material.

### Claim 16 (depends on 13)

The method of claim 13, wherein said base substrate is a Ge-containing semiconductor substrate.

### Claim 17 (depends on 16)

The method of claim 16, wherein said Ge-containing semiconductor material comprises SiGe alloy.

### Claim 18 (depends on 13)

The method of claim 13, wherein said non-HF etchant is a non-HF containing acid.

### Claim 19 (depends on 18)

The method of claim 18, wherein said non-HF containing acid is selected from the group consisting of HCl, HBr and HI and mixtures thereof.

### Claim 20 (depends on 13)

The method of claim 13, wherein said removing the sacrificial phosphide containing layer utilizing said non-HF containing etchant is performed at a temperature from room temperature up to, but not beyond a boiling point of the non-HF containing etchant.

### Claim 21 (depends on 13)

The method of claim 13, wherein after removing the sacrificial phosphide-containing layer and the semiconductor buffer layer from between the base substrate and the semiconductor device layer, said base substrate has a RMS surface roughness of from 0.1 nm to 0.5 nm or within ±0.5 nm of an initial RMS roughness.

### Claim 22 (depends on 13)

The method of claim 13, wherein said sacrificial phosphide-containing layer is composed of a compound of phosphorus and at least one element that is less electronegative than said phosphorus.

### Claim 23 (depends on 22)

The method of claim 22, wherein said sacrificial phosphide-containing layer comprises InAlP, InGaP, InAsP, GaAsP, InGaAlP, InGaAsP, GaP, InP and phosphide-containing alloys.

### Claim 24 (depends on 13)

The method of claim 13, wherein said sacrificial phosphide-containing layer is a different semiconductor material than said base substrate.