# US 8,465,799 B2 · Method for preparation of flat step-free silicon carbide surfaces

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- Number: US 8,465,799 B2
- Document ID: US8465799B2
- Status: Granted
- Kind: B2
- Application number: 12/212,940
- Filed: 2008-09-18
- Published: 2010-03-18
- Granted: 2013-06-18
- Earliest claimed: 2008-09-18
- Assignees: International Business Machines Corporation
- Applicants: James B. Hannon; Rudolf Tromp
- Inventors: James B. Hannon; Rudolf Tromp
- Web page: https://patentgrep.com/patent/US8465799B2

## CPC

- H10P 14/20: of semiconductor materials
- H10D 62/8325: {Silicon carbide}
- H10P 14/2904: {Silicon carbide}
- H10P 14/3406: {Carbon, e.g. diamond-like carbon}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

Techniques for producing atomic step-free silicon carbide surfaces are provided. In one aspect, a method for eliminating atomic steps from a silicon carbide surface is provided. The method comprises the following step. The silicon carbide and a silicon-containing gas are contacted at a temperature, background pressure, and for a length of time sufficient to re-arrange the silicon carbide to an atomic step-free surface. The silicon carbide surface can be the top of a mesa or the bottom of a hole patterned in a silicon carbide wafer.

## Claims

### Claim 1

A method for eliminating atomic steps from a silicon carbide surface, comprising the step of:
contacting the silicon carbide and a silicon-containing gas at a temperature, background pressure, and for a length of time sufficient to re-arrange the silicon carbide to an atomic step-free surface while preventing decomposition of the silicon carbide into graphene, wherein the temperature is from about 900 degrees Celsius to about 1,200 degrees Celsius.

### Claim 2 (depends on 1)

The method of claim 1, wherein the silicon-containing gas replaces silicon atoms that evaporate at the contacting temperature thereby preventing a net loss of silicon atoms.

### Claim 3 (depends on 1)

The method of claim 1, wherein the silicon-containing gas is formed from a silicon-containing compound selected from the group consisting of: silane, disilane, dichlorosilane, methylsilane, chlorosilane, trichlorosilane, dimethylsilane and trimethylsilane.

### Claim 4 (depends on 1)

The method of claim 1, wherein the background pressure is from about 1×10−10 Torr to about one Torr.

### Claim 5 (depends on 1)

The method of claim 1, wherein the background pressure is from about 1×10−6 Torr to about one Torr.

### Claim 6 (depends on 1)

The method of claim 1, wherein the background pressure is from about 1×10−4 Torr to about 1×10−2 Torr.

### Claim 7 (depends on 1)

The method of claim 1, wherein the length of time is less than or equal to about five hours.

### Claim 8 (depends on 1)

The method of claim 1, wherein the length of time is less than or equal to about two hours.

### Claim 9 (depends on 1)

The method of claim 1, wherein the temperature employed facilitates individual silicon carbide molecules to be released from and diffuse across the surface.

### Claim 10 (depends on 1)

The method of claim 1, wherein the temperature employed facilitates individual silicon and carbon atoms to be released from and diffuse across the surface.

### Claim 11 (depends on 1)

The method of claim 1, further comprising the step of:
permitting the silicon carbide to decompose after the atomic step-free surface is formed into silicon atoms, which evaporate, and carbon atoms which form one or more graphene layers.

### Claim 12 (depends on 11)

The method of claim 11, wherein the step of permitting the silicon carbide to decompose further comprises the step of:
increasing the temperature, while keeping the background pressure constant, to a temperature at which the silicon carbide decomposes into the graphene.

### Claim 13 (depends on 11)

The method of claim 11, wherein the step of permitting the silicon carbide to decompose further comprises the step of:
decreasing the background pressure, while keeping the temperature constant, to a pressure at which the silicon carbide decomposes into the graphene.

### Claim 14 (depends on 1)

The method of claim 1, wherein the silicon-containing gas is a silicon-containing vapor comprising atomic silicon generated from an evaporation source.

### Claim 15 (depends on 14)

The method of claim 14, wherein the evaporation source is a silicon wafer.

### Claim 16 (depends on 1)

The method of claim 1, wherein the silicon carbide surface comprises a top of a mesa patterned in a silicon carbide wafer.

### Claim 17 (depends on 16)

The method of claim 16, wherein the mesa has a height of from about one nanometer to about one micrometer.

### Claim 18 (depends on 1)

The method of claim 1, wherein the silicon carbide surface comprises a bottom of a hole patterned in a silicon carbide wafer.

### Claim 19 (depends on 18)

The method of claim 18, wherein the hole has a depth of from about one nanometer to about one micrometer.