# US 9,040,364 B2 · Carbon nanotube devices with unzipped low-resistance contacts

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- Number: US 9,040,364 B2
- Document ID: US9040364B2
- Status: Granted
- Kind: B2
- Application number: 13/664,008
- Filed: 2012-10-30
- Published: 2014-05-01
- Granted: 2015-05-26
- Earliest claimed: 2012-10-30
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: Damon B. Farmer; Aaron D. Franklin; Joshua T. Smith; George S. Tulevski
- Web page: https://patentgrep.com/patent/US9040364B2

## CPC

- H10P 14/3462: {Nanowires}
- H10D 30/60: Insulated-gate field-effect transistors [IGFET] (H10D30/40 takes precedence)
- H10D 62/118: {Nanostructure semiconductor bodies}
- H10D 62/119: {Nanowire, nanosheet or nanotube semiconductor bodies}
- H10D 62/121: {oriented parallel to substrates}
- H10K 10/84: Ohmic electrodes, e.g. source or drain electrodes
- H10K 85/221: {Carbon nanotubes}
- H10P 14/3464: {Nanotubes}
- B82Y 99/00: Subject matter not provided for in other groups of this subclass
- Y10S 977/742: Carbon nanotubes, CNTs
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A method of creating a semiconductor device is disclosed. An end of a carbon nanotube is unzipped to provide a substantially flat surface. A contact of the semiconductor device is formed. The substantially flat surface of the carbon nanotube is coupled to the contact to create the semiconductor device. An energy gap in the unzipped end of the carbon nanotube may be less than an energy gap in a region of the carbon nanotube outside of the unzipped end region.

## Claims

### Claim 1

A method of forming a semiconductor device, the method comprising:
unzipping an end of a carbon nanotube to provide a carbon nanotube with a substantially flat surface at the end;
forming a contact of the semiconductor device; and
coupling the substantially flat surface at the end of the carbon nanotube to the contact to form the semiconductor device.

### Claim 2 (depends on 1)

The method of claim 1, wherein unzipping the end of the carbon nanotube further comprises one of forming a longitudinal cut at the end of the carbon nanotube and forming a spiral cut at the end of the carbon nanotube.

### Claim 3 (depends on 1)

The method of claim 1, further comprising coupling a free edge of the substantially flat surface of the carbon nanotube to the contact.

### Claim 4 (depends on 1)

The method of claim 1, further comprising sandwiching the substantially flat surface of the carbon nanotube between the contact and a substrate of the semiconductor device.

### Claim 5 (depends on 4)

The method of claim 4, further comprising disposing the carbon nanotube on a surface of a high-k dielectric, unzipping the end of the carbon nanotube to provide the substantially flat surface on the surface of the high-k dielectric, and forming the contact on top of the substantially flat surface of the carbon nanotube.

### Claim 6 (depends on 1)

The method of claim 1, wherein coupling the substantially flat surface to the contact reduces a contact resistance between the contact and the carbon nanotube.

### Claim 7 (depends on 1)

The method of claim 1, wherein the contact is one of a source contact and a drain contact and the carbon nanotube is a gated channel of the semiconductor device.

### Claim 8

A method of forming a carbon nanotube field-effect transistor, comprising:
unzipping an end segment of the carbon nanotube and unrolling the unzipped end segment to form a substantially planar surface; and
coupling the unzipped end segment of the carbon nanotube to a contact to form the carbon nanotube field-effect transistor.

### Claim 9 (depends on 8)

The method of claim 8, wherein unzipping the end segment of the carbon nanotube and unrolling the unzipped end segment to form a substantially planar surface reduces an energy gap in the end segment of the carbon nanotube.

### Claim 10 (depends on 8)

The method of claim 8, wherein unzipping the end segment further comprises one of forming a longitudinal cut at the end segment of the carbon nanotube and forming a spiral cut at the end segment of the carbon nanotube.

### Claim 11 (depends on 8)

The method of claim 8, further comprising coupling an edge of the substantially planar surface to the contact.

### Claim 12 (depends on 8)

The method of claim 8, further comprising sandwiching the unzipped end segment of the carbon nanotube between the contact and a substrate of the field effect transistor.

### Claim 13 (depends on 8)

The method of claim 8, wherein coupling the unzipped end segment to the contact reduces a contact resistance between the contact and the carbon nanotube.

### Claim 14 (depends on 8)

The method of claim 8, wherein the contact is one of a source contact and a drain contact and the carbon nanotube is a gated channel.

### Claim 15

A method of reducing a contact resistance in a carbon nanotube transistor, comprising:
unzipping an end segment of a carbon nanotube to provide a carbon nanotube with an unzipped end segment;
forming a planar surface from the unzipped end segment of the carbon nanotube; and
coupling the planar surface to a contact of the carbon nanotube transistor.

### Claim 16 (depends on 15)

The method of claim 15, wherein unzipping the end segment of the carbon nanotube further comprises one of forming a longitudinal cut at an end of the carbon nanotube and forming a spiral cut at an end of the carbon nanotube.

### Claim 17 (depends on 15)

The method of claim 15, wherein coupling the planar surface to the contact further comprises forming a covalent bond between the contact and a dangling carbon bond at an edge of the planar surface.

### Claim 18 (depends on 15)

The method of claim 15, further comprising sandwiching the planar surface between a substrate and the contact.

### Claim 19 (depends on 15)

The method of claim 15, wherein unzipping the end segment reduces an energy gap in the unzipped segment with respect the energy gap of the carbon nanotube outside of the unzipped segment.

### Claim 20 (depends on 15)

The method of claim 15, wherein the contact is one of a source contact and a drain contact and the carbon nanotube is a gated channel.