Patent US4657658A successfully refreshed from Google Patents.
US4657658A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor devices
Assignee: National Research Development Corp UK
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Filing: 1985-11-07
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Granted: 1987-04-14
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Expires: 2005-11-07
Abstract
Abstract A semiconductor integrated circuit for sensing a physico-chemical property of an ambient includes a pair of semiconductor devices (Q1, Q2) having a similar geometric and physical structure, one device (Q1) being sensitive to the property, the other being insensitive to the property, together with a differential amplifier (A1, A2, A3, A4, A5) having feedback connection to one of the pair of semiconductor devices.
Inventors
- 👤 Alastair Sibbald
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:50
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/30; H03F1/301; G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/414; G01N27/4148; Y; Y10; Y10S; Y10S435/00; Y10S435/817
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
103 words
A semiconductor integrated circuit including: a first semiconductor device sensitive to a physico-chemical property of an ambient to which it is exposed and capable of producing an output signal dependent on said physico-chemical property, a second semiconductor device insensitive to said physico-chemical property but having a geometry and physical structure substantially identical with that of said first semiconductor device and being substantially in isothermal contact with said first semiconductor device, and differential amplifier means having an input coupled to outputs of said first and second semiconductor devices and having an output coupled to an input of one of said first and second semiconductors.
Claim 2
Dependent Claim
103 words
A semiconductor integrated circuit including: a first semiconductor device sensitive to a physico-chemical property of an ambient to which it is exposed and capable of producing an output signal dependent on said physico-chemical property, a second semiconductor device insensitive to said physico-chemical property but having a geometry and physical structure substantially identical with that of said first semiconductor device and being substantially in isothermal contact with said first semiconductor device, and differential amplifier means having an input coupled to outputs of said first and second semiconductor devices and having an output coupled to an input of one of said first and second semiconductors.
Claim 3
Dependent Claim
19 words
A semiconductor integrated circuit as claimed in claim 1 wherein said first and second semiconductor devices are field-effect transistors.
Claim 4
Dependent Claim
28 words
A semiconductor integrated circuit as claimed in claim 2 wherein said first semiconductor device includes a silicon substrate having channel region overlain by a layer of silcon nitride.
Claim 5
Dependent Claim
29 words
A semiconductor integrated circuit as claimed in claim 3 wherein said first semiconductor device includes a layer of silicon dioxide between said layer of silicon nitride and said substrate.
Claim 6
Dependent Claim
24 words
A semiconductor integrated circuit as claimed in claim 4 further including a layer of an ion-sensing polymeric film overlaying said layer of silicon nitride.
Claim 7
Dependent Claim
17 words
A semiconductor integrated circuit as claimed in claim 5 wherein said polymeric film incoporates an ionsphere dopant.
Claim 8
Dependent Claim
20 words
A semiconductor integrated circuit as claimed in claim 6 wherein said ionsphere-doped polymeric film includes valinomycin, bis(2-ethylexyl)adipate and polyvinyl chloride.
Claim 9
Dependent Claim
18 words
A semiconductor integrated circuit as claimed in any one of claims 1-7 having a protective overlay of polyimide.
References Cited (Backward Citations)
US3703650A
Cited
US4385274A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-13 | 1990-10-13 | 1991-04-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-13 | 1994-10-13 | 1995-04-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-13 | 1998-10-13 | 1999-04-14 | $7700.00 | Window Closed / Lapsed |