# US 2013/0157447 A1 · Single crystal silicon tfts made by lateral crystallization from a nanowire seed

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- Number: US 2013/0157447 A1
- Document ID: US20130157447A1
- Status: Published application
- Kind: A1
- Application number: 13/330,516
- Filed: 2011-12-19
- Published: 2013-06-20
- Earliest claimed: 2011-12-19
- Assignees: Palo Alto Research Center Incorporated
- Inventors: Robert A. Street; Sourobh Raychaudhuri
- Web page: https://patentgrep.com/patent/US20130157447A1

## CPC

- H10P 14/3211: {Silicon, silicon germanium or germanium}
- H10D 30/0323: {comprising monocrystalline silicon}
- H10P 14/271: {characterised by the preparation of substrate for selective deposition}
- H10P 14/279: {Vapour-liquid-solid growth}
- H10P 14/3256: {Microstructure}
- H10P 14/3411: {Silicon, silicon germanium or germanium}
- H10P 14/3462: {Nanowires}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A method can include depositing a thin metal film on a substrate of a sample, establishing a metal island on the substrate by patterning the thin metal film, and annealing the sample to de-wet the metal island and form a metal droplet from the metal island. The method can also include growing a nanowire on the substrate using the metal droplet as a catalyst, depositing a thin film of a semiconductor material on the sample, annealing the sample to allow for lateral crystallization to form a crystal grain, and patterning the crystal grain to establish a crystal island. An electronic device can be fabricated using the crystal island.

## Claims

### Claim 1

A method, comprising:
depositing a thin metal film on a substrate of a sample;
establishing a metal island on the substrate by patterning the thin metal film on the substrate;
annealing the sample to de-wet the metal island and form a metal droplet from the metal island;
growing a nanowire on the substrate using the metal droplet as a catalyst, wherein the nanowire comprises a first semiconductor material;
depositing a thin film of a second semiconductor material on the sample;
annealing the sample to allow for lateral crystallization to form a crystal grain;
patterning the crystal grain to establish a crystal island; and
processing an electronic device using the crystal island.

### Claim 2 (depends on 1)

The method of claim 1, wherein the metal comprises one of a group consisting of: gold, copper, and nickel, wherein the first semiconductor material comprises one of a group consisting of: silicon (Si), gallium nitride (GaN), and gallium arsenide (GaAs), and wherein the second semiconductor material comprises one of a group consisting of: Si, GaN, and GaAs.

### Claim 3 (depends on 1)

The method of claim 1, further comprising performing a light etching to remove any portion of the metal island that did not re-wet.

### Claim 4 (depends on 1)

The method of claim 1, further comprising depositing a silicon oxide overcoat on the sample subsequent to the depositing of the thin film of the second semiconductor material on the sample.

### Claim 5 (depends on 1)

The method of claim 1, further comprising stripping unwanted silicon subsequent to the patterning of the crystal grain.

### Claim 6 (depends on 1)

The method of claim 1, wherein depositing the thin film of the second semiconductor material is performed at a time subsequent to depositing the thin metal film on the substrate.

### Claim 7 (depends on 1)

The method of claim 1, wherein the thin metal film has a thickness of no more than approximately 5 nanometers.

### Claim 8 (depends on 1)

The method of claim 1, wherein the metal droplet has a diameter of no more than approximately 200 nanometers.

### Claim 9 (depends on 1)

The method of claim 1, wherein the electronic device comprises a thin film transistor (TFT).

### Claim 10 (depends on 1)

The method of claim 1, wherein growing the nanowire comprises using vapor-liquid-solid (VLS) techniques or vapor-solid-solid (VSS) techniques.

### Claim 11

A method, comprising:
depositing a thin film of a first semiconductor material on a sample;
depositing a thin metal film on the sample;
establishing a metal island on the sample by patterning the thin metal film;
annealing the sample to de-wet the metal island and form a metal droplet from the metal island;
growing a nanowire on the substrate using the metal droplet as a catalyst, wherein the nanowire comprises a second semiconductor material;
annealing the sample to allow for lateral crystallization to form a crystal grain;
patterning the crystal grain to establish a crystal island; and
processing an electronic device using the crystal island.

### Claim 12 (depends on 11)

The method of claim 11, wherein the metal comprises one of a group consisting of: gold, copper, and nickel, wherein the first semiconductor material comprises one of a group consisting of: silicon (Si), gallium nitride (GaN), and gallium arsenide (GaAs), and wherein the second semiconductor material comprises one of a group consisting of: Si, GaN, and GaAs.

### Claim 13 (depends on 11)

The method of claim 11, further comprising performing a light etching to remove any portion of the metal island that did not re-wet.

### Claim 14 (depends on 11)

The method of claim 11, further comprising depositing a silicon oxide overcoat on the sample subsequent to the growing of the nanowire.

### Claim 15 (depends on 11)

The method of claim 11, wherein the thin metal film has a thickness of no more than approximately 5 nanometers.

### Claim 16 (depends on 11)

The method of claim 11, wherein the metal droplet has a diameter of no more than approximately 200 nanometers.

### Claim 17 (depends on 11)

The method of claim 11, wherein growing the nanowire comprises using vapor-liquid-solid (VLS) techniques or vapor-solid-solid (VSS) techniques.

### Claim 18

A method, comprising:
depositing a thin metal film on a substrate of a sample;
establishing a metal island on the substrate by patterning the thin metal film on the substrate;
annealing the sample to de-wet the metal island and form a metal droplet from the metal island;
growing a nanowire on the substrate using the metal droplet as a catalyst, wherein the nanowire comprise a first semiconductor material;
depositing a thin film of a second semiconductor material on the sample;
patterning the thin film of the second semiconductor material to establish a crystal island;
annealing the sample to allow for lateral crystallization to form the crystal island as a crystal grain; and
processing an electronic device using the crystal island.

### Claim 19 (depends on 18)

The method of claim 18, wherein the metal comprises one of a group consisting of: gold, copper, and nickel, wherein the first semiconductor material comprises one of a group consisting of: silicon (Si), gallium nitride (GaN), and gallium arsenide (GaAs), and wherein the second semiconductor material comprises one of a group consisting of: Si, GaN, and GaAs.

### Claim 20 (depends on 18)

The method of claim 18, further comprising performing a light etching to remove any portion of the metal island that did not re-wet.

### Claim 21 (depends on 18)

The method of claim 18, further comprising depositing a silicon oxide overcoat on the sample subsequent to the depositing of the thin film of the second semiconductor material on the sample.

### Claim 22 (depends on 18)

The method of claim 18, wherein the thin metal film has a thickness of no more than approximately 5 nanometers.

### Claim 23 (depends on 18)

The method of claim 18, wherein the metal droplet has a diameter of no more than approximately 200 nanometers.

### Claim 24 (depends on 18)

The method of claim 18, wherein growing the nanowire comprises using vapor-liquid-solid (VLS) techniques or vapor-solid-solid (VSS) techniques.