US5085746A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of fabricating scanning tunneling microscope tips
Assignee: North Carolina State University
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Filing: 1990-09-10
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Granted: 1992-02-04
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Expires: 2010-09-10
Abstract
Abstract A method of fabricating a double-tapered scanning tunneling microscope comprises (a) immersing one end of the tip in a bath of an acidic aqueous etchant solution containing an alkaline earth salt, with the wire positioned substantially perpendicularly to the surface of the solution; and (b) etching the wire at about 25 volts root mean squared (rms) alternating current (ac) until a double-tapered tip is formed thereon. The etching step is preferably followed by a polishing step which comprises (c) providing a thin film of a second acidic aqueous etchant solution containing an alkaline earth salt; then (d) contacting said electrode tip to the thin film: and then (e) etching the tip at about 2 volts rms ac to thereby polish the tip. Also disclosed is a method inhibiting the formation of carbon on a scanning tunneling microscope tip which comprises (a) positioning a wire in an etchant solution and then (b) etching the wire while excluding carbon dioxide therefrom. Double-tapered scanning tunneling microscope tip comprised of an elongate wire and methods of using the same are also disclosed.
Inventors
- 👤 Inga H. Musselman
- 👤 Phillip E. Russell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 14:19
CPC Classifications
G; G01; G01Q; G01Q60/00; G01Q60/10; G01Q60/16; B; B82; B82Y; B82Y35/00; C; C25; C25F; C25F3/00; C25F3/02; C25F3/16; H; H01; H01J; H01J9/00; H01J9/02; H01J9/022; H01J9/025; H01J2201/00; H01J2201/30; H01J2201/304; H01J2201/30446; H01J2201/30453; H01J2201/30457
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
151 words
A method of fabricating a double-tapered scanning tunneling microscope tip from a wire formed from platinum, iridium, or a platinum/iridium alloy, said tip comprising an elongate wire, and intermediate conical portion formed at one end of said elongate wire, and an end conical portion formed at the apex of said intermediate conical portion and axially therewith, with a tip formed at the apex of said end conical portion, said method comprising: (a) immersing one end of the wire in a bath of an acidic aqueous etchant solution containing an alkaline earth salt, with the wire positioned substantially perpendicularly to the surface of the solution; and (b) etching said wire in said bath to form said intermediate conical portion; and then (c) ceasing said etching step while said tip is immersed in and in electrical contact with said bath so that said end conical portion is formed on said intermediate conical portion.
Claim 2
Independent Claim
151 words
A method of fabricating a double-tapered scanning tunneling microscope tip from a wire formed from platinum, iridium, or a platinum/iridium alloy, said tip comprising an elongate wire, and intermediate conical portion formed at one end of said elongate wire, and an end conical portion formed at the apex of said intermediate conical portion and axially therewith, with a tip formed at the apex of said end conical portion, said method comprising: (a) immersing one end of the wire in a bath of an acidic aqueous etchant solution containing an alkaline earth salt, with the wire positioned substantially perpendicularly to the surface of the solution; and (b) etching said wire in said bath to form said intermediate conical portion; and then (c) ceasing said etching step while said tip is immersed in and in electrical contact with said bath so that said end conical portion is formed on said intermediate conical portion.
Claim 3
Dependent Claim
20 words
A method according to claim 1 wherein the wire has a diameter of from about 0.1 to about 0.5 millimeters.
Claim 4
Dependent Claim
20 words
A method according to claim 1 wherein the wire has a diameter of from about 0.20 to about 0.25 millimeters.
Claim 5
Dependent Claim
29 words
A method according to claim 1, wherein said free one end of said wire is immersed in said bath a depth of from about 1.5 to about 2.0 millimeters.
Claim 6
Dependent Claim
25 words
A method according to claim 1, which wire is formed from an alloy consisting essentially of 80% by weight platinum and 20% by weight iridium.
Claim 7
Dependent Claim
15 words
A method according to claim 1, wherein said alkaline earth salt is CaCl 2 .
Claim 8
Dependent Claim
12 words
A method according to claim 1, wherein said etchant solution contains HCl.
Claim 9
Dependent Claim
31 words
A method according to claim 1, wherein said etchant solution is comprised of, by volume, 60% aqueous saturated CaCl 2 solution, 36%, H 2 O, and 4% 12 Molar HCl solution.
Claim 10
Dependent Claim
19 words
A method according to claim 1, wherein said etching step is carried out in a carbon dioxide free environment.
Claim 11
Dependent Claim
19 words
A method according to claim 1, wherein said step (e) is carried out in a carbon dioxide free environment.
Claim 12
Independent Claim
66 words
A method of inhibiting the formation of carbon on a scanning tunneling microscope tip during etching thereof, comprising: (a) positioning said tip in an etchant solution, which tip is formed from platinum, iridium, or a platinum/iridium alloy; and then (b) etching said tip while excluding carbon dioxide therefrom, wherein sufficient carbon dioxide is excluded to inhibit the formation of a contaminating carbon layer on said tip.
Claim 13
Independent Claim
66 words
A method of inhibiting the formation of carbon on a scanning tunneling microscope tip during etching thereof, comprising: (a) positioning said tip in an etchant solution, which tip is formed from platinum, iridium, or a platinum/iridium alloy; and then (b) etching said tip while excluding carbon dioxide therefrom, wherein sufficient carbon dioxide is excluded to inhibit the formation of a contaminating carbon layer on said tip.
Claim 14
Dependent Claim
16 words
A method according to claim 11, wherein said etchant solution is substantially free of carbon dioxide.
Claim 15
Dependent Claim
21 words
A method according to claim 11 wherein said etching step is carried out in an atmosphere substantially free of carbon dioxide.
Claim 16
Dependent Claim
20 words
A method according to claim 11, wherein said etching step is carried out in an atmosphere consisting essentially of nitrogen.
Claim 17
Dependent Claim
25 words
A method according to claim 11, wherein said wire is positioned in said etchant solution by immersing the wire in a bath of etchant solution.
Claim 18
Dependent Claim
21 words
A method according to claim 11, wherein said etchant solution comprises an acidic aqueous etchant solution containing an alkaline earth salt.
Claim 19
Dependent Claim
22 words
A method according to claim 11, wherein said etching step is carried out in an atmosphere consisting essentially of an inert gas.
Claim 20
Dependent Claim
39 words
A method according to claim 17, wherein said etching step is carried out in an enclosed chamber, further comprising the step of purging the enclosed chamber to a humidity of less than 15 percent prior to said etching step.
Claim 21
Dependent Claim
40 words
A method according to claim 11, wherein said etchant solution is comprised of water which has been boiled to render said etchant solution sufficiently free of carbon dioxide to inhibit the formation of a contaminating carbon layer on said tip.
Claim 22
Independent Claim
123 words
A method of fabricating a double-tapered scanning tunneling microscope tip from a wire formed from platinum, iridium or a platinum/iridium alloy, comprising: (a) immersing one end of the wire in a bath of an acidic aqueous etchant solution containing an alkaline earth salt, with the wire positioned substantially perpendicularly to the surface of the solution; and (b) etching said wire at about 25 volts root mean squared (rms) alternating current (ac) until a double tapered tip is formed; and then (c) providing a thin film of a second acidic aqueous etchant solution containing an alkaline earth salt; then (d) contacting said tip to said thin film; and then (e) etching said tip at about 2 volts rms ac to thereby polish said tip.
Claim 23
Independent Claim
123 words
A method of fabricating a double-tapered scanning tunneling microscope tip from a wire formed from platinum, iridium or a platinum/iridium alloy, comprising: (a) immersing one end of the wire in a bath of an acidic aqueous etchant solution containing an alkaline earth salt, with the wire positioned substantially perpendicularly to the surface of the solution; and (b) etching said wire at about 25 volts root mean squared (rms) alternating current (ac) until a double tapered tip is formed; and then (c) providing a thin film of a second acidic aqueous etchant solution containing an alkaline earth salt; then (d) contacting said tip to said thin film; and then (e) etching said tip at about 2 volts rms ac to thereby polish said tip.
Claim 24
Dependent Claim
20 words
A method according to claim 20, wherein said alkaline earth salt in said second etchant solution is CaCl 2 .
Claim 25
Dependent Claim
13 words
A method according to claim 20, wherein said second etchant solution contains HCl.
Claim 26
Dependent Claim
32 words
A method according to claim 20, wherein said second etchant solution is comprised of, by volume, 60% aqueous saturated CaCl 2 solution, 36% H 2 O, and 4% 12 Molar HCl solution.
Claim 27
Independent Claim
61 words
A method of inhibiting the formation of carbon on a scanning tunneling microscope tip during etching thereof, comprising: (a) positioning wire in an etchant solution, which wire is formed from platinum, iridium, or a platinum/iridium alloy; and then (b) etching the wire while excluding carbon dioxide therefrom, wherein said etching step is carried out in an atmosphere consisting essentially of nitrogen.
Claim 28
Independent Claim
61 words
A method of inhibiting the formation of carbon on a scanning tunneling microscope tip during etching thereof, comprising: (a) positioning wire in an etchant solution, which wire is formed from platinum, iridium, or a platinum/iridium alloy; and then (b) etching the wire while excluding carbon dioxide therefrom, wherein said etching step is carried out in an atmosphere consisting essentially of nitrogen.
Claim 29
Dependent Claim
25 words
A method according to claim 24, wherein said wire is positioned in said etchant solution by immersing the wire in a bath of etchant solution.
Claim 30
Dependent Claim
28 words
A method according to claim 24, wherein said wire is positioned in said etchant solution by contacting the wire to a thin film formed from an etchant solution.
Claim 31
Dependent Claim
21 words
A method according to claim 24, wherein said etchant solution comprises an acidic aqueous etchant solution containing an alkaline earth salt.
Claim 32
Independent Claim
70 words
A method of inhibiting the formation of carbon on a scanning tunneling microscope tip during etching thereof, comprising: (a) positioning a wire in an etchant solution, which wire is formed from platinum, iridium, or a platinum/iridium alloy; and then (b) etching the wire while excluding carbon dioxide therefrom, wherein said wire is positioned in said etchant solution by contacting the wire to a thin film formed from an etchant solution.
Claim 33
Independent Claim
70 words
A method of inhibiting the formation of carbon on a scanning tunneling microscope tip during etching thereof, comprising: (a) positioning a wire in an etchant solution, which wire is formed from platinum, iridium, or a platinum/iridium alloy; and then (b) etching the wire while excluding carbon dioxide therefrom, wherein said wire is positioned in said etchant solution by contacting the wire to a thin film formed from an etchant solution.
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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) | 1995-02-03 | 1995-08-05 | 1996-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-02-03 | 1999-08-05 | 2000-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-02-03 | 2003-08-05 | 2004-02-04 | $7700.00 | Window Closed / Lapsed |