US4592238A
Expired / Lapsed
US
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Laser-recrystallized diaphragm pressure sensor and method of making
Assignee: Spectramed Inc
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Filing: 1985-04-15
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Granted: 1986-06-03
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Expires: 2005-04-15
Abstract
Abstract A pressure sensor includes a diaphragm and an overpressure stop, with a gap inbetween for displacement of the diaphragm in response to an applied pressure, the diaphragm being formed of laser-recrystallized polysilicon. Data extraction is accomplished either by depositing or forming four piezoresistors on the diaphragm and connecting them as the elements of a Wheatstone bridge circuit or by using the appropriately doped laser-recrystallized diaphragm as a piezoresistor itself.
Inventors
- 👤 Heinz H. Busta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:48
CPC Classifications
B; B81; B81C; B81C1/00; B81C1/00015; B81C1/00134; B81C1/00158; G; G01; G01L; G01L9/00; G01L9/0041; G01L9/0042; G01L9/0051; G01L9/0052; G01L9/0054; B81B; B81B2201/00; B81B2201/02; B81B2201/0264; B81B2203/00; B81B2203/01; B81B2203/0127; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49103
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
42 words
A pressure sensor comprising: a diaphragm and an overpressure stop opposed from one another, said diaphragm and overpressure stop having a gap therebetween for displacement of said diaphragm in response to an applied pressure, said diaphragm being formed of laserrecrystallized polycrystalline silicon.
Claim 2
Dependent Claim
42 words
A pressure sensor comprising: a diaphragm and an overpressure stop opposed from one another, said diaphragm and overpressure stop having a gap therebetween for displacement of said diaphragm in response to an applied pressure, said diaphragm being formed of laserrecrystallized polycrystalline silicon.
Claim 3
Dependent Claim
23 words
The sensor of claim 1 wherein said overpressure stop is formed of a high temperature material that is substantially insensitive to HF etches.
Claim 4
Dependent Claim
12 words
The sensor of claim 2 wherein said material is single crystal silicon.
Claim 5
Dependent Claim
25 words
The sensor of claim 3 further comprising means for measuring the change in displacement of said diaphragm in response to the change in applied pressure.
Claim 6
Dependent Claim
51 words
The sensor of claim 4 wherein said measuring means is accomplished by connecting leads to said diaphragm for conducting through said diaphragm changes in current generated by changes in displacement of said diaphragm and wherein said diaphragm is formed of p-type silicon and said overpressure stop is formed of n-type silicon.
Claim 7
Dependent Claim
23 words
The sensor of claim 5 wherein said diaphragm has an area of about 200 micrometers×200 micrometers and a thickness of about 2 micrometers.
Claim 8
Dependent Claim
23 words
The sensor of claim 5 wherein said diaphragm has an area of about 100 micrometers×100 micrometers and a thickness of about 2 micrometers.
Claim 9
Dependent Claim
30 words
The sensor of claim 5 wherein said diaphragm has an area of from 30 micrometers×30 micrometers to about 50 micrometers×50 micrometers and a thickness of about 0.1 to 2 micrometers.
Claim 10
Dependent Claim
37 words
The sensor of claim 4 wherein said measuing means comprises four piezoresistive resistors ion implanted within said diaphragm and connected as the elements of a Wheatstone bridge circuit, said resistors being p-type and said diaphragm being n-type.
Claim 11
Dependent Claim
17 words
The sensor of claim 9 wherein said diaphragm has an area of at least 100 micrometers×100 micrometers.
Claim 12
Dependent Claim
17 words
The sensor of claim 10 wherein said diaphragm has an area of at least 100 micrometers×100 micrometers.
Claim 13
Dependent Claim
17 words
The sensor of claim 9 wherein said diaphragm has an area of at least 200 micrometers×200 micrometers.
Claim 14
Dependent Claim
33 words
The sensor of claim 2 further comprising means for measuring the change in displacement of said diaphragm in response to the change in applied pressure, said measuring means being coupled to said diaphragm.
Claim 15
Dependent Claim
32 words
The sensor of claim 13 wherein measuring means is accomplished by connecting leads to said diaphragm for conducting through said diaphragm changes in current generated by changes in displacement of said diaphragm.
Claim 16
Dependent Claim
23 words
The sensor of claim 14 wherein said diaphragm has an area of about 200 micrometers×200 micrometers and a thickness of about 2 micrometers.
Claim 17
Dependent Claim
23 words
The sensor of claim 14 wherein said diaphragm has an area of about 100 micrometers×100 micrometers and a thickness of about 2 micrometers.
Claim 18
Dependent Claim
28 words
The sensor of claim 14 wherein said diaphragm has an area of from 30 micrometers×30 micrometers to about 50 micrometers×50 micrometers and a thickness of about 0.1-2 micrometers.
Claim 19
Dependent Claim
37 words
The sensor of claim 13 wherein said measuring means comprises four piezoresistive resistors ion implanted within said diaphragm and connected as the elements of a Wheatstone bridge circuit, said resistors being p-type and said diaphragm being n-type.
Claim 20
Dependent Claim
17 words
The sensor of claim 18 wherein said diaphragm has an area of at least 100 micrometers×100 micrometers.
Claim 21
Independent Claim
99 words
A method of making a pressure transducer comprising the steps of: (a) forming an oxide post on the surface of a substrate, the area of said post corresponding to the area of a diaphragm to be formed; (b) forming an etch channel on the surface of said substrate, said etch channel surrounding said oxide post; (c) depositing a layer of polycrystalline silicon on said substrate covering said oxide post; (d) laser-recrystallizing said polycrystalline layer, thereby forming said diaphragm; (e) laterally etching said oxide with an oxide etching solution , thereby forming a gap between said diaphragm and said substrate.
Claim 22
Independent Claim
99 words
A method of making a pressure transducer comprising the steps of: (a) forming an oxide post on the surface of a substrate, the area of said post corresponding to the area of a diaphragm to be formed; (b) forming an etch channel on the surface of said substrate, said etch channel surrounding said oxide post; (c) depositing a layer of polycrystalline silicon on said substrate covering said oxide post; (d) laser-recrystallizing said polycrystalline layer, thereby forming said diaphragm; (e) laterally etching said oxide with an oxide etching solution , thereby forming a gap between said diaphragm and said substrate.
Claim 23
Dependent Claim
14 words
The method of claim 20 wherein said substrate is formed of single crystal silicon.
Claim 24
Dependent Claim
24 words
The method of claim 20 wherein said substrate is formed of a high temperature material that is substantially insensitive to said oxide etching solution.
Claim 25
Dependent Claim
44 words
The method of claim 20 wherein step (a) is replaced by (a1) etching said substrate to form a cavity within said substrate, the area of said cavity corresponding to the area of the diaphragm to be formed, (a2) depositing an oxide within said cavity.
Claim 26
Dependent Claim
31 words
The method of claim 20 further comprising steps: (f) forming four piezoresistive resistors on said laser-recrystallized layer; and (g) connecting said resistors as the four elements of a Wheatstone bridge circuit.
Claim 27
Dependent Claim
14 words
The method of claim 20 further comprising step: (h) connecting leads to said diaphragm.
Claim 28
Dependent Claim
56 words
A multi-element sensor comprising: an n×m array of diaphragms having a common overpressure stop; each diaphragm having a gap between itself and said overpressure stop for displacement of said diaphragm in response to an applied pressure; each diaphragm being formed of laser-recrystallized polycrystalline silicon; wherein n is at least 3 and m is at least 1.
Claim 29
Dependent Claim
56 words
A multi-element sensor comprising: an n×m array of diaphragms having a common overpressure stop; each diaphragm having a gap between itself and said overpressure stop for displacement of said diaphragm in response to an applied pressure; each diaphragm being formed of laser-recrystallized polycrystalline silicon; wherein n is at least 3 and m is at least 1.
References Cited (Backward Citations)
US3858150A
Cited
US4003127A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-06-02 | 1989-12-02 | 1990-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-02 | 1993-12-02 | 1994-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-02 | 1997-12-02 | 1998-06-03 | $7700.00 | Window Closed / Lapsed |