US4873871A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mechanical field effect transistor sensor
Assignee: Motorola Solutions Inc
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Filing: 1988-06-17
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Granted: 1989-10-17
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Expires: 2008-06-17
Abstract
Abstract A mechanical field effect transistor sensor which has a drain and a source on a semiconductor portion, and a moveable gate which causes conduction between the drain and source when the gate is in proximity or touching the semiconductor portion. The gate in its preferred embodiment comprises a cantilever microbeam which allows movement of the gate up or down with respect to the semiconductor portion when a force is applied to the microbeam. The microbeam can be replaced with a diaphragm or a simply supported beam. The gate is coupled to an external voltage source which supplies a voltage to the gate causing the conduction between drain and source. Another embodiment uses a piezoelectric material for the gate which generates a voltage when it is compressed or expanded due to forces caused by changes in acceleration and magnetic fields.
Inventors
- 👤 Monty W. Bai
- 👤 Douglas J. Huhmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:28
CPC Classifications
H; H10; H10D; H10D48/00; H10D48/50; G; G01; G01B; G01B7/00; G01B7/16; G01H; G01H11/00; G01H11/06; G01L; G01L9/00; G01L9/0098; G01P; G01P15/00; G01P15/02; G01P15/08; G01P15/12; G01P15/124
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
101 words
A mechanical field effect transistor sensor comprising: semiconductor portion means for conducting a current when a surface concentration of electrons of said semiconductor portion means is altered; deflectable semiconductor means for sensing movement of the sensor; a bottom portion of said deflectable semiconductor means secured above said semiconductor portion means; said deflectable semiconductor means deflectable in a vertical direction with respect to said semiconductor portion means; gate means for altering said surface electron concentration of said semiconductor portion; said gate means micromachined onto a bottom side of a deflecting portion of said deflectable semiconductor means, and adjacent to said semiconductor portion.
Claim 2
Dependent Claim
101 words
A mechanical field effect transistor sensor comprising: semiconductor portion means for conducting a current when a surface concentration of electrons of said semiconductor portion means is altered; deflectable semiconductor means for sensing movement of the sensor; a bottom portion of said deflectable semiconductor means secured above said semiconductor portion means; said deflectable semiconductor means deflectable in a vertical direction with respect to said semiconductor portion means; gate means for altering said surface electron concentration of said semiconductor portion; said gate means micromachined onto a bottom side of a deflecting portion of said deflectable semiconductor means, and adjacent to said semiconductor portion.
Claim 3
Dependent Claim
74 words
A sensor according to claim 1 wherein said semiconductor portion means comprises: drain means for receiving a current from a primary source; source means for outputting said current; semiconductor substrate means for allowing said current to flow from said drain means to said source means when said surface electron concentration is altered; and said drain means and said source means fixedly secured to a plane of said semiconductor substrate means below said gate means.
Claim 4
Dependent Claim
89 words
A sensor according to claim 2 wherein said deflectable semiconductor means further comprises: end support means for securing said deflectable semiconductor means above said semiconductor means, said end support means secured to said semiconductor means; said deflecting portion deflecting when the sensor is subject to movement, said deflection proportional to a force caused by said movement; connector means for connecting said gate means to a voltage source; and said connector means including a first end coupled to said gate means and a second end coupled to said voltage source.
Claim 5
Dependent Claim
15 words
A sensor according to claim 3 wherein said deflectable support means comprises a cantilever microbeam.
Claim 6
Dependent Claim
14 words
A sensor according to claim 3 wherein said deflectable support means comprises a diaphragm.
Claim 7
Dependent Claim
11 words
A sensor according to claim 1 wherein the sensor is micromachined.
Claim 8
Dependent Claim
102 words
A micromachined mechanical field effect transistor sensor comprising: semiconductor portion means for conducting a current when a surface concentration of electrons of said semiconductor portion means is altered; deflectable semiconductor means for sensing movement of the sensor; a bottom portion of said deflectable semiconductor means secured above said semiconductor portion means; said deflectable semiconductor means deflectable in a vertical direction with respect to said semiconductor portion means; gate means for altering said surface electron concentration of said semiconductor portion; said gate means micromachined onto a bottom side of a deflecting portion of said deflectable semiconductor means, and adjacent to said semiconductor portion.
Claim 9
Dependent Claim
102 words
A micromachined mechanical field effect transistor sensor comprising: semiconductor portion means for conducting a current when a surface concentration of electrons of said semiconductor portion means is altered; deflectable semiconductor means for sensing movement of the sensor; a bottom portion of said deflectable semiconductor means secured above said semiconductor portion means; said deflectable semiconductor means deflectable in a vertical direction with respect to said semiconductor portion means; gate means for altering said surface electron concentration of said semiconductor portion; said gate means micromachined onto a bottom side of a deflecting portion of said deflectable semiconductor means, and adjacent to said semiconductor portion.
Claim 10
Dependent Claim
79 words
A micromachined mechanical field effect transistor sensor according to claim 7 wherein said semiconductor portion means comprises: drain means for receiving a current from a primary source; source means for outputting said current; semiconductor substrate means for allowing said current to flow from said drain means to said source means when said surface electron concentration is altered; and said drain means and said source means fixedly secured to a plane of said semiconductor substrate means below said gate means.
Claim 11
Dependent Claim
94 words
A micromachined mechanical field effect transistor sensor according to claim 7 wherein said deflectable semiconductor means further comprises: end support means for securing said deflectable semiconductor means above said semiconductor means, said end support means secured to said semiconductor means; said deflecting portion deflecting when the sensor is subject to movement, said deflection proportional to a force caused by said movement; connector means for connecting said gate means to a voltage source; and said connector means including a first end coupled to said gate means and a second end coupled to said voltage source.
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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) | 1992-10-16 | 1993-04-17 | 1993-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-16 | 1997-04-17 | 1997-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-16 | 2001-04-17 | 2001-10-17 | $7700.00 | Window Closed / Lapsed |