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US4906968A
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Percolating cermet thin film thermistor
Assignee: Cornell Research Foundation Inc
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Filing: 1988-10-04
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Granted: 1990-03-06
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Expires: 2008-10-04
Abstract
Abstract A cermet thin film resistor having small particles of a refractory metal embedded in a ceramic insulator at compositions near the percolation transition. The cermets are produced by co-deposition in a dual-electron beam evaporator. The refractory metal is typically Mo or Pt. The insulator is typically a Al 2 O 3 , although other insulators, for example SiO 2 may be used. Deposition occurs onto a suitable substrate such as a sapphire under an oxygen environment, typically 10 -5 Torr O 2 with the stage heated in the range of typically 400° C. Such is done to increase the size of the metallic regions. The microstructure is 10-50 Å embedded metal in the ceramic. The resulting films are in the range of 1500 Å thick which provides a film having a typical resistivity of 400 mΩ - cm which may then be patterned using lithography techniques to form two or four terminal resistors.
Inventors
- 👤 Neil Gershenfeld
- 👤 Watt W. Webb
- 👤 Jeffrey E. VanCleve
- 👤 Joseph V. Mantese
- 👤 Eric T. Swartz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:50
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/04; H01C7/041
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
45 words
A thermometry element comprising: an oxide substrate, and a thin cermet film deposited on said substrate and having the formula M-C where M is a refractory metal and C is a ceramic insulator processed just below the percolation transition, said cermet having 45-50% metal volume.
Claim 2
Dependent Claim
45 words
A thermometry element comprising: an oxide substrate, and a thin cermet film deposited on said substrate and having the formula M-C where M is a refractory metal and C is a ceramic insulator processed just below the percolation transition, said cermet having 45-50% metal volume.
Claim 3
Dependent Claim
10 words
The element of claim 1, wherein the metal is Pt.
Claim 4
Dependent Claim
10 words
The element of claim 1, wherein the metal is Mo.
Claim 5
Dependent Claim
11 words
The element of claim 1, wherein the ceramic insulator is sapphire.
Claim 6
Dependent Claim
16 words
The element of claim 1, wherein said thin cermet film has a thickness approximately 1,500 Å.
Claim 7
Dependent Claim
24 words
The element of claim 1, wherein said cermet comprises a metallic particle size in the range of 10-50 Å embedded in said ceramic insulator.
Claim 8
Dependent Claim
20 words
The element of claim 1, wherein said thin film is patterned and further comprises at least a pair of terminals.
Claim 9
Dependent Claim
14 words
The element of claim 1, wherein said oxide substrate is a single crystal sapphire.
Claim 10
Dependent Claim
12 words
The element of claim 1, wherein said substrate is SiO 2 .
Claim 11
Dependent Claim
17 words
The element of claim 1, wherein said element has a temperature sensitive range of 50 mk-300 mk.
Claim 12
Dependent Claim
37 words
A temperature sensitive resistor comprising; an oxide substrate, and a thin film cermet made from a refractory metal-ceramic mixture deposited on said substrate and processed to just below the percolation transition, said cermet having 45-50 metal volume.
Claim 13
Dependent Claim
37 words
A temperature sensitive resistor comprising; an oxide substrate, and a thin film cermet made from a refractory metal-ceramic mixture deposited on said substrate and processed to just below the percolation transition, said cermet having 45-50 metal volume.
Claim 14
Dependent Claim
10 words
The element of claim 11, wherein the metal is Pt.
Claim 15
Dependent Claim
10 words
The element of claim 11, wherein the metal is Mo.
Claim 16
Dependent Claim
10 words
The element of claim 11, wherein the ceramic is sapphire.
Claim 17
Dependent Claim
16 words
The element of claim 11, wherein said thin cermet film has a thickness approximately 1,500 Å.
Claim 18
Dependent Claim
22 words
The element of claim 11, wherein said cermet having a particle size in the range of 10-50 Åmetal embedded in said ceramic.
Claim 19
Dependent Claim
20 words
The element of claim 11, wherein said thin film is patterned and further comprises at least a pair of terminals.
Claim 20
Dependent Claim
14 words
The element of claim 11, wherein said oxide substrate is a single crystal sapphire.
Claim 21
Dependent Claim
12 words
The element of claim 11, wherein said substrate is SiO 2 .
Claim 22
Dependent Claim
17 words
The element of claim 11, wherein said element has a temperature sensitive range of 50 mk-300 mk.
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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) | 1993-03-05 | 1993-09-04 | 1994-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-05 | 1997-09-04 | 1998-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-05 | 2001-09-04 | 2002-03-06 | $7700.00 | Window Closed / Lapsed |