US5600174A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Suspended single crystal silicon structures and method of making same
Assignee: Leland Stanford Junior University
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Filing: 1994-10-11
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Granted: 1997-02-04
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Expires: 2014-10-11
Abstract
Abstract Temperature-sensitive transducers and other circuitry are manufactured by an electrochemical post-processing etch on an integrated circuit fabricated using a conventional CMOS process. Tetramethyl ammonium hydroxide or another anisotropic etchant having similar characterisics is used to selectively etch exposed front-side regions of a p-type silicon substrate, leaving n-type wells suspended from oxide beams. Circuits in the n-wells are thermally and electrically insulated from the substrate.
Inventors
- 👤 Richard J. Reay
- 👤 Erno H. Klaassen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:07
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/17; H10D62/351; H10D62/357; H10D62/364; G; G01; G01F; G01F1/00; G01F1/68; G01F1/684; G01F1/6845; G01K; G01K7/00; G01K7/01; G01K7/015
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
101 words
An integrated circuit incorporating a suspended single crystal silicon structure, comprising: a p-substrate; a pit etched in said p-substrate; at least one dielectric beam extending over said pit; an n-well suspended over said pit by said at least one dielectric beam, said at least one dielectric beam providing mechanical support and thermal insulation of said n-well; circuitry having electrical characteristics effected by temperature, at least a portion of said circuitry being located in said n-well and being thermally isolated in said n-well; and electrically conductive traces in said at least one dielectric beam connecting said thermally isolated circuitry to external circuits.
Claim 2
Dependent Claim
101 words
An integrated circuit incorporating a suspended single crystal silicon structure, comprising: a p-substrate; a pit etched in said p-substrate; at least one dielectric beam extending over said pit; an n-well suspended over said pit by said at least one dielectric beam, said at least one dielectric beam providing mechanical support and thermal insulation of said n-well; circuitry having electrical characteristics effected by temperature, at least a portion of said circuitry being located in said n-well and being thermally isolated in said n-well; and electrically conductive traces in said at least one dielectric beam connecting said thermally isolated circuitry to external circuits.
Claim 3
Dependent Claim
12 words
The device of claim 1, wherein said electrically conductive traces are aluminum.
Claim 4
Dependent Claim
20 words
The device of claim 1, wherein said circuitry comprises an MOS heating transistor for controlling the temperature in said n-well.
Claim 5
Dependent Claim
19 words
The device of claim 1, wherein said circuitry comprises a heating resistor for controlling the temperature in said n-well.
Claim 6
Dependent Claim
17 words
The device of claim 1, wherein said circuitry comprises a temperature sensor including at least one diode.
Claim 7
Dependent Claim
18 words
The device of claim 1, wherein said circuitry comprises a temperature sensor including at least one MOS transistor.
Claim 8
Dependent Claim
18 words
The device of claim 1, wherein said circuitry comprises a temperature sensor including at least one bipolar transistor.
Claim 9
Dependent Claim
18 words
The device of claim 1, wherein said circuitry comprises a temperature sensor including at least one temperature-sensitive resistor.
Claim 10
Dependent Claim
47 words
The device of claim 1, wherein said circuitry comprises a feedback mechanism including a heating transistor and a diode, said heating transistor acting as an actuator, said diode acting as a temperature sensor, and said feedback mechanism acting to keep said circuitry at a substantially constant temperature.
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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) | 2000-02-04 | 2000-08-05 | 2001-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-02-04 | 2004-08-05 | 2005-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-02-04 | 2008-08-05 | 2009-02-04 | $7700.00 | Window Closed / Lapsed |