US3831432A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Environment monitoring device and system
Assignee: Texas Instruments Inc
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Filing: 1972-09-05
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Granted: 1974-08-27
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Expires: 1992-09-05
Abstract
Abstract A monitoring system for characterizing the presence and concentration of selected substances in an environment is provided. The system includes a set of sensors which provide outputs responsive to substances adsorbed from the environment, at least one of the sensors having an output which differs from others in the set in its response to at least one substance being monitored. Preferably the sensors comprise adsorption field effect transistors respectively having chemically specific films in the gate region to enable preferential adsorption of preselected substances.
Inventors
- 👤 P Cox
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:01
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/0004; G01N33/0009; G01N33/0027; G01N33/0031; G01N27/00; G01N27/26; G01N27/403; G01N27/414; H; H10; H10D; H10D99/00
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
175 words
A system for determining the concentration of a plurality of selected substances in an environment comprising: a plurality of substantially identical semiconductor sensors, each of which includes means for effecting preferential adsorbing of specific ones of said selected substances to provide outputs correlatable to the respective concentration of each of said substances; each oF said semiconductor sensors including a semiconductor substrate of one conductivity type having spaced apart regions of opposite conductivity type extending from one surface thereof, the semiconductor material between said regions defining a channel having an initial pretermined conductance with a selected bias, said preferential adsorbing means comprising a chemically specific film disposed over said channel for enabling preferential adsorption of a respective one of said selected substances, and the conductance of said channel being variable from said initial predetermined value in response to the amount and type of substance adsorbed by said chemically specific film; and each of said semiconductor sensors serving as respective field effect transistors whose outputs are indicative of the concentration of specific ones of said selected substances.
Claim 2
Independent Claim
175 words
A system for determining the concentration of a plurality of selected substances in an environment comprising: a plurality of substantially identical semiconductor sensors, each of which includes means for effecting preferential adsorbing of specific ones of said selected substances to provide outputs correlatable to the respective concentration of each of said substances; each oF said semiconductor sensors including a semiconductor substrate of one conductivity type having spaced apart regions of opposite conductivity type extending from one surface thereof, the semiconductor material between said regions defining a channel having an initial pretermined conductance with a selected bias, said preferential adsorbing means comprising a chemically specific film disposed over said channel for enabling preferential adsorption of a respective one of said selected substances, and the conductance of said channel being variable from said initial predetermined value in response to the amount and type of substance adsorbed by said chemically specific film; and each of said semiconductor sensors serving as respective field effect transistors whose outputs are indicative of the concentration of specific ones of said selected substances.
Claim 3
Dependent Claim
28 words
A system as set forth in claim 1, wherein said film of each sensor essentially comprises silicon oxide having an exposed adsorbent surface substantially free of silicon-oxygen-carbon linkages.
Claim 4
Dependent Claim
24 words
A system as set forth in claim 2 wherein the thickness of each of said films is on the order of 50A or less.
Claim 5
Dependent Claim
53 words
A system as set forth in claim 2 wherein at least one of said films of essentially silicon oxide is modified by replacement of silanol hydroxide molecules in the surface region thereof with alkoxide groups to produce a hydrophobic exposed surface having a high sensitivity to a respective one of said selected substances.
Claim 6
Dependent Claim
37 words
A system as set forth in claim 2 wherein the exposed surface region of at least one of said films of essentially silicon oxide comprises a reaction product containing silicon-carbon bonding and substantially free of silicon-oxygen-carbon linkages.
Claim 7
Dependent Claim
29 words
A system as as set forth in claim 1, wherein said film of each sensor comprises a polymerized organo-silicon compound containing at least one preselected chemically selective functional group.
Claim 8
Dependent Claim
47 words
A system as set forth in claim 1, wherein said film of at least one sensor comprises silicon oxide having an exposed surface region of modified constituency, said exposed surface region of said film being formed of the reaction product of silicon oxide and a metal alkoxide.
Claim 9
Dependent Claim
26 words
A system as set forth in claim 7 wherein said metal alkoxide includes a metal selected from the group consisting of boron, aluminum, arsenic, and phosphorus.
Claim 10
Dependent Claim
118 words
A sensor for determining the concentration of a preselected substance in an environment in the vicinity of said sensor comprising: a semiconductor substrate of one conductivity type; first and second spaced apart regions of opposite conductivity type in said semiconductor substrate and extending to the surface of said substrate, the semiconductor material between said regions defining a channel having an initial predetermined conductance; and means covering said channel for preferentially adsorbing said preselected substance, the conductance of said channel being variable from said initial predetermined value in response to the amount and type of substance adsorbed by said means; and said sensor serving as a field effect transistor whose output is indicative of the concentration of said substance.
Claim 11
Dependent Claim
118 words
A sensor for determining the concentration of a preselected substance in an environment in the vicinity of said sensor comprising: a semiconductor substrate of one conductivity type; first and second spaced apart regions of opposite conductivity type in said semiconductor substrate and extending to the surface of said substrate, the semiconductor material between said regions defining a channel having an initial predetermined conductance; and means covering said channel for preferentially adsorbing said preselected substance, the conductance of said channel being variable from said initial predetermined value in response to the amount and type of substance adsorbed by said means; and said sensor serving as a field effect transistor whose output is indicative of the concentration of said substance.
Claim 12
Dependent Claim
128 words
An adsorption field effect transistor sensor for detecting the concentration of a preselected substance in an environment comprising: a. a semiconductor substrate of one conductivity type; b. at least two spaced apart regions of opposite conductivity type extending from one surface of said substrate defining a channel therebetween having an initial predetermined conductance; and c. a chemically specific film overlying said channel, said film being formed of a material enabling preferential adsorption from said environment of a preselected substance; d. the conductance of said channel being variable from said initial predetermined value in response to the amount and type of substance adsorbed by said chemically specific film, whereby the output of said adsorption field effect transistor seNsor is indicative of the concentration of said substance in said environment.
Claim 13
Dependent Claim
128 words
An adsorption field effect transistor sensor for detecting the concentration of a preselected substance in an environment comprising: a. a semiconductor substrate of one conductivity type; b. at least two spaced apart regions of opposite conductivity type extending from one surface of said substrate defining a channel therebetween having an initial predetermined conductance; and c. a chemically specific film overlying said channel, said film being formed of a material enabling preferential adsorption from said environment of a preselected substance; d. the conductance of said channel being variable from said initial predetermined value in response to the amount and type of substance adsorbed by said chemically specific film, whereby the output of said adsorption field effect transistor seNsor is indicative of the concentration of said substance in said environment.
Claim 14
Dependent Claim
31 words
An adsorption field effect transistor sensor as set forth in claim 10, wherein said chemically specific film essentially comprises silicon oxide having an exposed adsorbent surface substantially free of silicon-oxygen-carbon linkages.
Claim 15
Dependent Claim
49 words
An adsorption field effect transistor sensor as set forth in claim 11, wherein said film of essentially silicon oxide is modified by replacement of silanol hydroxide molecules in the surface region thereof with alkoxide groups to produce a hydrophobic exposed surface having a high sensitivity to said preselected substance.
Claim 16
Dependent Claim
37 words
An adsorption field effect transistor sensor as set forth in claim 11, wherein the exposed surface region of said film of essentially silicon oxide comprises a reaction product containing silicon-carbon bonding and substantially free of silicon-oxygen-carbon linkages.
Claim 17
Dependent Claim
31 words
An adsorption field effect transistor sensor as set forth in claim 10, wherein said chemically specific film comprises a polymerized organo-silicon compound containing at least one preselected chemically selective functional group.
Claim 18
Dependent Claim
36 words
An adsorption field effect transistor sensor as set forth in claim 14, wherein the material of said substrate is silicon, and said film comprises the reaction product of the silicon substrate surface and said organo-silicon compound.
Claim 19
Dependent Claim
20 words
An adsorption field effect transistor sensor as set forth in claim 15, wherein said organo-silicon compound is an alkyl-triacetoxy silane.
Claim 20
Dependent Claim
48 words
An adsorption field effect transistor sensor as set forth in claim 10, wherein said chemically specific film comprises silicon oxide having an exposed surface region of modified constituency, said exposed surface region of said film being formed of the reaction product of silicon oxide and a metal alkoxide.
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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) | 1977-08-26 | 1978-02-25 | 1978-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-26 | 1982-02-25 | 1982-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-26 | 1986-02-25 | 1986-08-27 | $7700.00 | Window Closed / Lapsed |