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US4437969A
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Offset-gate chemical-sensitive field-effect transistors (OG-CHEMFETS) with electrolytically-programmable selectivity
Assignee: Bayer Corp
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Filing: 1982-04-08
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Granted: 1984-03-20
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Expires: 2002-04-08
Abstract
Abstract A selective chemosensitive microelectronic transducer is provided for the detection and measurement of chemical properties, by engineering a field-effect transistor such that source 6 and drain 7 regions are connected to bonding pads 2 and 4, and the semiconductor bulk connected to pad 1. The metal gate 8 is extended laterally to a remote area 9, and also to bonding pad 3 via a narrow metallization track 5 designed to support only a limited, predetermined electrical current in the manner of a fusible link. External electrical access to the device is achieved with wirebonding 14, and the device is selectively sealed with an inert, impervious encapsulation material 10 such that only gate area 9 remains exposed. Electroactive materials are deposited over the offset-gate area 9, or electrodeposited using connection through 8, 5 and 3. Subsequently, link 5 is open-circuited by pulsed electrical overload, creating a floating chemosensitive gate.
Inventors
- 👤 Arthur K. Covington
- 👤 Alastair Sibbald
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:55
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/20; H10D64/27; H10D64/311; H10D64/411; H10D64/511; H10D64/517; H10D64/519; G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/414; H10W; H10W20/00; H10W20/40; H10W20/49; H10W20/493; H10W72/00; H10W72/50; H10W72/531; H10W72/5363; Y; Y10; Y10S; Y10S435/00; Y10S435/817
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
128 words
A field-effect device comprising a semiconductor substrate, a source region located in a first surface of said substrate, a drain region located in said first surface and spaced apart from said source region, a layer of electrical insulator material overlying at least a portion of said source and drain regions and the surface of the substrate lying between said regions, a gate conductor disposed over said insulator material between said source and drain regions, a planar, offset gate comprising a conductive layer disposed on said first surface in a region remote from said source and drain regions, conductive means for electrically connecting said conductive layer to said gate conductor, an electrical conductor connected to said conductive layer, and a fusible link connected in series with said electrical conductor.
Claim 2
Dependent Claim
128 words
A field-effect device comprising a semiconductor substrate, a source region located in a first surface of said substrate, a drain region located in said first surface and spaced apart from said source region, a layer of electrical insulator material overlying at least a portion of said source and drain regions and the surface of the substrate lying between said regions, a gate conductor disposed over said insulator material between said source and drain regions, a planar, offset gate comprising a conductive layer disposed on said first surface in a region remote from said source and drain regions, conductive means for electrically connecting said conductive layer to said gate conductor, an electrical conductor connected to said conductive layer, and a fusible link connected in series with said electrical conductor.
Claim 3
Dependent Claim
24 words
A field-effect device according to claim 1 wherein said conductive means comprises a layer of conductive material disposed on the surface of said substrate.
Claim 4
Dependent Claim
21 words
A field-effect device according to claim 2 wherein said conductive means and said conductive layer are extensions of said gate conductor.
Claim 5
Dependent Claim
36 words
A field-effect device according to claim 1 further comprising a layer of electroactive material suitable for the detection and measurement of chemical properties disposed over at least a portion of the surface of said conductive layer.
Claim 6
Dependent Claim
52 words
A field-effect device according to claim 1 wherein said conductive means and said conductive layer are extensions of said gate conductor, said device further comprising a layer of electroactive material suitable for the detection and measurement of chemical properties disposed over at least a portion of the surface of said conductive layer.
Claim 7
Dependent Claim
50 words
A field-effect device according to claim 5 further comprising a coating of inert encapsulating material extending over that portion of said substrate including said source and drain regions to an area of said substrate between said source and drain regions and said conductive layer, whereby said electroactive material is exposed.
Claim 8
Dependent Claim
176 words
A field-effect device comprising a semiconductor substrate, a source region located in a first surface of said substrate, a drain region located in said first surface and spaced apart from said source region, an electrical insulator material overlying at least a portion of said source and drain regions and the surface of the substrate lying between said regions, a gate conductor disposed over said insulator material between said source and drain regions, said gate conductor extending laterally along said first surface to a region remote from said source and drain regions, the width of that portion of said gate conductor in said remote region being greater than the width of said gate conductor in the region of said source and drain regions, at least a portion of said lateral extension of said gate conductor being covered by at least one electroactive material suitable for the detection and measurement of chemical properties to which the device is exposed, an electrical conductor connected to said conductive layer, and a fusible link connected in series with said electrical conductor.
Claim 9
Dependent Claim
176 words
A field-effect device comprising a semiconductor substrate, a source region located in a first surface of said substrate, a drain region located in said first surface and spaced apart from said source region, an electrical insulator material overlying at least a portion of said source and drain regions and the surface of the substrate lying between said regions, a gate conductor disposed over said insulator material between said source and drain regions, said gate conductor extending laterally along said first surface to a region remote from said source and drain regions, the width of that portion of said gate conductor in said remote region being greater than the width of said gate conductor in the region of said source and drain regions, at least a portion of said lateral extension of said gate conductor being covered by at least one electroactive material suitable for the detection and measurement of chemical properties to which the device is exposed, an electrical conductor connected to said conductive layer, and a fusible link connected in series with said electrical conductor.
Claim 10
Dependent Claim
50 words
A field-effect device according to claim 7 further comprising a coating of inert encapsulating material extending over that portion of said substrate including said source and drain regions to an area of said substrate between said electroactive material and said source and drain regions whereby said electroactive material is exposed.
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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) | 1987-03-20 | 1987-09-19 | 1988-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-20 | 1991-09-19 | 1992-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-20 | 1995-09-19 | 1996-03-20 | $7700.00 | Window Closed / Lapsed |