# US 10,504,722 B2 · Growth of III-nitride semiconductors on thin van der Waals buffers for mechanical lift off and transfer

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- Number: US 10,504,722 B2
- Document ID: US10504722B2
- Status: Granted
- Kind: B2
- Application number: 16/043,456
- Filed: 2018-07-24
- Published: 2019-01-31
- Granted: 2019-12-10
- Earliest claimed: 2017-07-25
- Assignees: The United States of America as represented by the Secretary of the Air Force
- Applicants: Government of the United States, as represented by the Secretary of the Air Force
- Inventors: Michael R. Snure; Gene P. Siegel; Qing Paduano
- Web page: https://patentgrep.com/patent/US10504722B2

## CPC

- H10P 14/3248: {consisting of two layers}
- H10P 14/24: using chemical vapour deposition [CVD]
- H10P 14/2921: {being crystalline insulating materials}
- H10P 14/3206: {Carbon, e.g. diamond-like carbon}
- H10P 14/3216: {Nitrides}
- H10P 14/3236: {being chalcogenide semiconducting materials not being oxides, e.g. ternary compounds}
- H10P 14/3251: {consisting of three or more layers}
- H10P 14/3416: {Nitrides}
- H10P 14/38: {characterised by treatments done after the formation of the materials}
- H10P 95/11: {Separation of active layers from substrates}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A semiconductor device includes a mechanical release layer, such as a van der Waals buffer layer, with a predetermined material roughness and thickness adjacent to a first substrate; a nucleation layer adjacent to the mechanical release layer; and a first semiconductor layer attached to the nucleation layer. The first semiconductor layer, the nucleation layer, and a portion of the mechanical release layer are releasably connected to the first substrate. The predetermined material roughness and thickness of the mechanical release layer determines a bonding strength of the first semiconductor layer to the first substrate. The semiconductor device may include an aluminum nitride insert layer adjacent to the first semiconductor layer; an aluminum gallium nitride barrier layer adjacent to the aluminum nitride insert layer; and a second semiconductor layer adjacent to the aluminum gallium nitride barrier layer. The semiconductor device may include a second substrate attached to the released first semiconductor layer.

## Claims

### Claim 1

A semiconductor device comprising:
a first substrate;
a mechanical release layer comprising a predetermined material roughness and thickness adjacent to the first substrate;
a nucleation layer adjacent to the mechanical release layer; and
a first semiconductor layer attached to the nucleation layer,
wherein the first semiconductor layer, the nucleation layer, and a portion of the mechanical release layer are configured to be releasably connected to the first substrate,
wherein the predetermined material roughness and thickness of the mechanical release layer determines a bonding strength of the mechanical release layer to the first substrate, and
wherein the mechanical release layer comprises a substantially non-planar surface interfacing with the nucleation layer.

### Claim 2 (depends on 1)

The semiconductor device of claim 1, comprising:
an aluminum nitride insert layer adjacent to the first semiconductor layer;
an aluminum gallium nitride barrier layer adjacent to the aluminum nitride insert layer; and
a second semiconductor layer adjacent to the aluminum gallium nitride barrier layer.

### Claim 3 (depends on 1)

The semiconductor device of claim 1, comprising a second substrate attached to the released first semiconductor layer.

### Claim 4 (depends on 1)

The semiconductor device of claim 1, wherein the mechanical release layer comprises a van der Waals (vdW) buffer layer.

### Claim 5

A method comprising:
growing a van der Waals (vdW) buffer layer of a predetermined material roughness and thickness on a first substrate;
providing a metal organic precursor material on the vdW buffer layer, wherein a ratio of nitrogen to boron in the metal organic precursor material is greater than approximately 450 to 4800;
depositing a nucleation layer on the vdW buffer layer; and
growing a semiconductor layer on the nucleation layer,
wherein the semiconductor layer is characterized by a bonding strength to the first substrate that varies according to the predetermined material roughness and thickness of the vdW buffer layer.

### Claim 6 (depends on 5)

The method of claim 5, comprising:
removing the semiconductor layer from the first substrate; and
transferring the removed semiconductor layer to a second substrate.

### Claim 7 (depends on 6)

The method of claim 6, wherein removing the semiconductor layer from the first substrate comprises using a mechanical lift-off process.

### Claim 8 (depends on 5)

The method of claim 5, wherein the semiconductor layer comprises any of GaN, AlN, InN, and alloys thereof.

### Claim 9 (depends on 5)

The method of claim 5, comprising adjusting a temperature while growing the vdW buffer layer, wherein the bonding strength is further characterized by the temperature.

### Claim 10 (depends on 5)

The method of claim 5 wherein the nucleation layer is approximately between 5 nm and 50 nm.

### Claim 11 (depends on 5)

The method of claim 5, wherein depositing the nucleation layer on the vdW buffer layer further comprises crystallographically orienting the nucleation layer by exposing a surface of the vdW buffer layer to a metal organic precursor material.

### Claim 12

A method comprising:
depositing a van der Waals (vdW) buffer layer with a selected material roughness and thickness on a substrate, comprising:
depositing a vdW buffer layer having a RMS roughness value less than 0.1 nm, and
altering the vdW buffer layer to have a RMS roughness value of approximately 2 nm;
growing a nucleation layer on the vdW buffer layer by (i) pulsing a metal organic precursor material to the vdW buffer layer to fix a polarity of a surface of the nucleation layer thereby creating a seed layer, and (ii) growing a nucleation material on the seed layer;
growing a semiconductor structure, wherein the semiconductor is adhered to the substrate, and wherein a bonding strength of the semiconductor structure to the substrate is controlled by the selected material roughness and thickness of the vdW buffer layer; and
releasing the semiconductor structure from the substrate by removing at least a portion of the vdW buffer layer from the substrate.

### Claim 13 (depends on 12)

The method of claim 12, comprising adjusting a thickness of the vdW buffer layer to control the bonding strength of the semiconductor structure to the substrate.

### Claim 14 (depends on 12)

The method of claim 12, comprising depositing the vdW buffer layer at a temperature between approximately 900° C. to 1150° C. and a pressure of less than approximately 500 Torr.

### Claim 15 (depends on 12)

The method of claim 12, comprising controlling a mechanical strain in the semiconductor structure.

### Claim 16 (depends on 12)

The method of claim 12, comprising growing the nucleation layer to approximately 15 nm in thickness.