US6350488B1
Expired / Lapsed
US
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Mass synthesis method of high purity carbon nanotubes vertically aligned over large-size substrate using thermal chemical vapor deposition
Assignee: Iljin Nanotech Co Ltd
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Filing: 2000-06-09
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Granted: 2002-02-26
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Expires: 2020-06-09
Abstract
Abstract A method of synthesizing high purity carbon nanotubes vertically aligned over a large size substrate by thermal chemical vapor deposition (CVD). In the synthesis method, isolated nano-sized catalytic metal particles are formed over a substrate by etching, and purified carbon nanotubes are grown vertically aligned, from the catalytic metal particles by thermal CVD using a carbon source gas.
Inventors
- 👤 Cheol-jin Lee
- 👤 Jae-eun Yoo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:26
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/02; H01J9/022; H01J9/025; B; B82; B82Y; B82Y30/00; B82Y40/00; C; C01; C01B; C01B32/00; C01B32/15; C01B32/158; C01B32/16; C01B32/162; D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/127; B82Y10/00; C01B2202/00; C01B2202/08; C01B2202/20; C01B2202/30; H01J2201/00; H01J2201/30; H01J2201/304; H01J2201/30446; H01J2201/30453; H01J2201/30469; Y; Y10; Y10S; Y10S977/00; Y10S977/70; Y10S977/734; Y10S977/742; Y10S977/832; Y10S977/833; Y10S977/84; Y10S977/842; Y10S977/843; Y10S977/89; Y10S977/891
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
82 words
A method of synthesizing carbon nanotubes, comprising: forming a metal catalyst layer over a substrate; etching the metal catalyst layer to form isolated nano-sized catalytic metal particles evenly distributed over an area of said substrate on which said metal catalyst layer was formed; and growing carbon nanotubes from said isolated nano-sized catalytic metal particles by thermal chemical vapor deposition (CVD) in which a carbon source gas is supplied to a thermal CVD apparatus to form carbon nanotubes vertically aligned over the substrate.
Claim 2
Independent Claim
82 words
A method of synthesizing carbon nanotubes, comprising: forming a metal catalyst layer over a substrate; etching the metal catalyst layer to form isolated nano-sized catalytic metal particles evenly distributed over an area of said substrate on which said metal catalyst layer was formed; and growing carbon nanotubes from said isolated nano-sized catalytic metal particles by thermal chemical vapor deposition (CVD) in which a carbon source gas is supplied to a thermal CVD apparatus to form carbon nanotubes vertically aligned over the substrate.
Claim 3
Dependent Claim
23 words
The method of claim 1 , wherein the metal catalyst layer is formed of cobalt, nickel, iron or an alloy of the same.
Claim 4
Dependent Claim
46 words
The method of claim 1 , wherein forming the isolated nano-sized catalytic metal particles is performed by a gas etching method in which one etching gas selected from the group consisting of ammonia gas, hydrogen gas and hydride gas is thermally decomposed for use in etching.
Claim 5
Dependent Claim
46 words
The method of claim 3 , wherein the etching gas is ammonia, and the gas etching method is performed at a temperature of 700 to 1000° C. while supplying the ammonia gas at a flow rate of 80 to 400 sccm for 10 to 30 minutes.
Claim 6
Dependent Claim
41 words
The method of claim 1 , wherein growing the carbon nanotubes is performed at a temperature of 700 to 1000° C. while supplying the carbon source gas at a flow rate of 20 to 200 sccm for 10 to 60 minutes.
Claim 7
Dependent Claim
26 words
The method of claim 1 , wherein forming the catalytic metal particles and forming the carbon nanotubes are in-situ performed in the same thermal CVD apparatus.
Claim 8
Dependent Claim
48 words
The method of claim 1 , wherein forming the isolated nano-sized catalytic metal particles is performed by a plasma etching method in which one gas selected from the group consisting of ammonia gas, hydrogen gas and hydride gas is used to create a plasma for use in etching.
Claim 9
Dependent Claim
83 words
The method of claim 7 , wherein the plasma etching includes the steps of forming a plasma under the processing condition of a frequency of 13.6 MHz, a gas pressure of 0.1 to 10 Torr, and a power of 50 to 200 watts, by supplying ammonia gas, hydrogen gas or hydride gas to the reaction chamber at a flow rate of 30 to 300 sccm, and the step of etching with the plasma at 350 to 600° C. for 5 to 30 minutes.
Claim 10
Dependent Claim
27 words
The method of claim 1 , wherein forming the isolated nano-sized catalytic metal particles is performed by a wet etching method using a hydrogen fluoride series etchant.
Claim 11
Dependent Claim
38 words
The method according to claim 9 , wherein said wet etching method includes the steps of immersing said substrate on which a metal catalyst layer is formed into a hydrogen fluoride series etchant for 1 to 5 minutes.
Claim 12
Dependent Claim
20 words
The method of claim 9 , wherein following said wet etching method, a dry etching using a gas is performed.
Claim 13
Dependent Claim
26 words
The method of claim 1 , wherein forming the isolated nano-sized catalytic metal particles is performed by photolithography using a photoresist pattern as an etching mask.
Claim 14
Dependent Claim
40 words
The method of claim 1 , wherein, in forming the carbon nanotubes, one gas selected from the group consisting of ammonia gas, hydrogen gas and hydride gas is supplied to the thermal CVD apparatus along with the carbon source gas.
Claim 15
Dependent Claim
29 words
The method of claim 1 , before forming the metal catalyst layer, further comprising forming an insulating layer to prevent reaction between the substrate and the metal catalyst layer.
Claim 16
Dependent Claim
27 words
The method of claim 1 , after forming the carbon nanotubes, further comprising exhausting the carbon source gas using an inert gas from the thermal CVD apparatus.
Claim 17
Dependent Claim
24 words
The method of claim 1 , after forming the carbon nanotubes, further comprising in-situ purifying the carbon nanotubes in the same thermal CVD apparatus.
Claim 18
Dependent Claim
36 words
The method of claim 16 , wherein in-situ purifying the carbon nanotubes is performed with a purification gas selected from the group consisting of ammonia gas, hydrogen gas, oxygen gas and a mixture of these gases.
Claim 19
Dependent Claim
27 words
The method of claim 17 , after in-situ purifying the carbon nanotubes, further comprising exhausting the purification gas using an inert gas from the thermal CVD apparatus.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2005-02-25 | 2005-08-27 | 2006-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-02-25 | 2009-08-27 | 2010-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-02-25 | 2013-08-27 | 2014-02-26 | $7700.00 | Window Closed / Lapsed |