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US5393647A
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Method of making superhard tips for micro-probe microscopy and field emission
Assignee: Individual
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Filing: 1993-07-16
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Granted: 1995-02-28
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Expires: 2013-07-16
Abstract
Abstract Forming micro-probe tips for an atomic force microscope, a scanning tunneling microscope, a beam electron emission microscope, or for field emission, by first thinning a tip of a first material, such as silicon. The tips are then reacted with a second material, such as atoms from an organic or ammonia vapor, at a temperature of about 1000° C.±200° C. and vacuum conditions for several minutes. Vapors such as methane, propane or acetylene will be converted to SiC or WC while ammonia will be converted to Si 3 N 4 . The converted material will have different physical, chemical and electrical properties. For example, a SiC tip will be superhard, approaching diamond in hardness. Electrically conductive tips are suitable for field emission.
Inventors
- 👤 Armand P. Neukermans
- 👤 Timothy G. Slater
- 👤 Linda E. Whittlesey
- 👤 Sean S. Cahill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:40
CPC Classifications
G; G01; G01Q; G01Q70/00; G01Q70/16; B; B81; B81C; B81C1/00; B81C1/00642; B81C1/0065; B81C1/00682; B82; B82Y; B82Y35/00; G01Q70/08; G01Q70/14; H; H01; H01J; H01J9/00; H01J9/02; H01J9/022; H01J9/025; B81B; B81B2201/00; B81B2201/12; H01J2209/00; H01J2209/02; H01J2209/022; H01J2209/0223; H01J2209/0226
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
98 words
A method of making superhard tips for micro-probe microscopy or field emission comprising, etching a tip of a first material, thinning the tip to a desired shape and aspect ratio suited to atomic force microscopy, and reacting the tip at an elevated temperature with an organic or ammonia vapor until at least an outer portion of the tip is converted to a compound having atoms of the first material and atoms of the vapor while essentially maintaining said shape and aspect ratio, the converted compound having changed physical, chemical and electrical properties with respect to the first material.
Claim 2
Independent Claim
98 words
A method of making superhard tips for micro-probe microscopy or field emission comprising, etching a tip of a first material, thinning the tip to a desired shape and aspect ratio suited to atomic force microscopy, and reacting the tip at an elevated temperature with an organic or ammonia vapor until at least an outer portion of the tip is converted to a compound having atoms of the first material and atoms of the vapor while essentially maintaining said shape and aspect ratio, the converted compound having changed physical, chemical and electrical properties with respect to the first material.
Claim 3
Dependent Claim
11 words
The method of claim 1 wherein said first material is silicon.
Claim 4
Dependent Claim
11 words
The method of claim 1 wherein said first material is tungsten.
Claim 5
Dependent Claim
12 words
The method of claim 1 wherein said vapor is an aliphatic compound.
Claim 6
Dependent Claim
14 words
The method of claim 4 wherein said aliphatic compound is acetylene, methane or propane.
Claim 7
Dependent Claim
12 words
The method of claim 2 wherein said converted compound is silicon carbide.
Claim 8
Dependent Claim
12 words
The method of claim 1 wherein said converted compound is electrically conductive.
Claim 9
Dependent Claim
12 words
The method of claim 2 wherein said converted compound is silicon nitride.
Claim 10
Dependent Claim
12 words
The method of claim 2 wherein said converted compound is tungsten carbide.
Claim 11
Dependent Claim
30 words
The method of claim 1 wherein said converted compound is SiC and said reacting step is carried out at a temperature greater than 800° C. and less than 1100° C.
Claim 12
Dependent Claim
33 words
The method of claim 1 wherein said reacting step is carried out at least until a surface layer of the tip having a thickness of 100 Å consists essentially of said converted compound.
Claim 13
Dependent Claim
16 words
The method of claim 1 wherein said desired aspect ratio is at least 3 to 1.
Claim 14
Independent Claim
79 words
A method of making tips for micro-probe microscopy or field emission comprising, patterning and etching a silicon post on a support member, shaping the post into a silicon tip having a desired sharpness and aspect ratio for atomic force microscopy and an essentially oxide-free surface, reacting the tip with an organic or ammonia vapor, thereby converting at least a portion of the surface of the tip into a material harder than silicon, including maintaining said sharpness and aspect ratio.
Claim 15
Independent Claim
79 words
A method of making tips for micro-probe microscopy or field emission comprising, patterning and etching a silicon post on a support member, shaping the post into a silicon tip having a desired sharpness and aspect ratio for atomic force microscopy and an essentially oxide-free surface, reacting the tip with an organic or ammonia vapor, thereby converting at least a portion of the surface of the tip into a material harder than silicon, including maintaining said sharpness and aspect ratio.
Claim 16
Dependent Claim
13 words
The method of claim 13 wherein said organic vapor is an aliphatic compound.
Claim 17
Dependent Claim
14 words
The method of claim 14 wherein said aliphatic compound is methane, acetylene or propane.
Claim 18
Dependent Claim
12 words
The method of claim 13 wherein said converted material is silicon carbide.
Claim 19
Dependent Claim
12 words
The method of claim 13 wherein said converted material is silicon nitride.
Claim 20
Dependent Claim
20 words
The method of claim 13 wherein said reacting step is carried out for a time between 2 and 20 minutes.
Claim 21
Dependent Claim
27 words
The method of claim 13 wherein said reacting step is carried out until a working end of the tip is converted to said material harder than silicon.
Claim 22
Dependent Claim
31 words
The method of claim 13 wherein said reacting step is carried out at least until the top 100 Å of the tip is completely converted to said material harder than silicon.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-02-27 | 1998-08-29 | 1999-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-27 | 2002-08-29 | 2003-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-27 | 2006-08-29 | 2007-02-28 | $7700.00 | Window Closed / Lapsed |