US5250170A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gas sensor having metal-oxide semiconductor layer
Assignee: Ricoh Co Ltd
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Filing: 1991-03-13
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Granted: 1993-10-05
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Expires: 2011-03-13
Abstract
Abstract A gas sensor includes a substrate, a heater member formed on the base member, a gas sensitive structure formed on the heater member by a process comprising the following steps of forming a stacked layer structure on the heater member, the stacked layer structure including at least a metal-oxide semiconductor layer and an insulating film, and carrying out a heat treatment with respect to the stacked layer structure so that a constituent of the insulating film is diffused in spaces among crystal particles of the metal-oxide semiconductor layer, and electrode layers are in contact with the gas sensitive structure.
Inventors
- 👤 Shinji Yagawara
- 👤 Wasaburo Ohta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:39
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
116 words
A gas sensor comprising: a base member including a heater member for generating heat; a metal-oxide semiconductor layer in which a resistance thereof is changed by a gas which is in contact with said metal-oxide semiconductor layer, said metal-oxide semiconductor layer being formed on said base member; an insulating thin film stacked on said metal-oxide semiconductor layer so as to cover a whole surface of said metal-oxide semiconductor layer; and electrodes, in contact with said metal-oxide semiconductor layer, for detecting a change in the resistance of said metal-oxide semiconductor layer, wherein said metal-oxide layer has a portion in which a material of said insulating thin film fills up spaces among crystals of said metal-oxide semiconductor layer.
Claim 2
Dependent Claim
116 words
A gas sensor comprising: a base member including a heater member for generating heat; a metal-oxide semiconductor layer in which a resistance thereof is changed by a gas which is in contact with said metal-oxide semiconductor layer, said metal-oxide semiconductor layer being formed on said base member; an insulating thin film stacked on said metal-oxide semiconductor layer so as to cover a whole surface of said metal-oxide semiconductor layer; and electrodes, in contact with said metal-oxide semiconductor layer, for detecting a change in the resistance of said metal-oxide semiconductor layer, wherein said metal-oxide layer has a portion in which a material of said insulating thin film fills up spaces among crystals of said metal-oxide semiconductor layer.
Claim 3
Dependent Claim
24 words
A gas sensor as claimed in claim 1, wherein said metal-oxide semiconductor layer has a thickness falling into a range of 500 A-5000 A.
Claim 4
Dependent Claim
24 words
A gas sensor as claimed in claim 1, wherein said insulating thin film has a thickness falling into a range of 50 A-500 A.
Claim 5
Dependent Claim
35 words
A gas sensor as claimed in claim 1, wherein said metal-oxide semiconductor layer is made of oxide of one material selected from the group consisting of tin, titanium, indium, nickel, tungsten, cadmium, iron, and zinc.
Claim 6
Dependent Claim
31 words
A gas sensor as claimed in claim 1, wherein said insulating thin film is made of one material selected from the group consisting of SiO.sub.2, Al.sub.2 O.sub.3, Ta.sub.2 O.sub.5, and Mgo.
Claim 7
Dependent Claim
41 words
A gas sensor as claimed in claim 1, wherein said heater member has a heater layer which generates heat when power is supplied from an external power supply to said heater layer and an insulating layer formed on said heater layer.
Claim 8
Dependent Claim
135 words
A gas sensor comprising: a base member including a heater member for generating heat; a stacked layer structure formed on said base member, said stacked layer structure comprising; a plurality of metal-oxide semiconductor layers in which a resistance thereof is changed by a gas which is in contact with said metal-oxide semiconductor layers; and one or a plurality of insulating thin films, said metal-oxide semiconductor layers and said one or a plurality of insulating thin films being alternately stacked; and electrodes, which are in contact with said metal-oxide semiconductor layers, for detecting a change in the resistance of said metal-oxide semiconductor layers, wherein each of said metal-oxide semiconductor layers has a portion in which a material of each of said insulating thin films fills up spaces among crystals of each of said metal-oxide semiconductor layers.
Claim 9
Dependent Claim
135 words
A gas sensor comprising: a base member including a heater member for generating heat; a stacked layer structure formed on said base member, said stacked layer structure comprising; a plurality of metal-oxide semiconductor layers in which a resistance thereof is changed by a gas which is in contact with said metal-oxide semiconductor layers; and one or a plurality of insulating thin films, said metal-oxide semiconductor layers and said one or a plurality of insulating thin films being alternately stacked; and electrodes, which are in contact with said metal-oxide semiconductor layers, for detecting a change in the resistance of said metal-oxide semiconductor layers, wherein each of said metal-oxide semiconductor layers has a portion in which a material of each of said insulating thin films fills up spaces among crystals of each of said metal-oxide semiconductor layers.
Claim 10
Dependent Claim
26 words
A gas sensor as claimed in claim 7, wherein each of said metal-oxide semiconductor layers has a thickness falling into a range of 55 A-5000 A.
Claim 11
Dependent Claim
26 words
A gas sensor as claimed in claim 7, wherein each of said insulating thin films has a thickness falling into a range of 100 A-1000 A.
Claim 12
Dependent Claim
37 words
A gas sensor as claimed in claim 7, wherein each of said metal-oxide semiconductor layer is made of oxide of one material selected from the group consisting of tin, titanium, indium, nickel, tungsten, cadmium, iron, and zinc.
Claim 13
Dependent Claim
33 words
A gas sensor as claimed in claim 7, wherein each of said insulting thin films is made of one material selected from the group consisting of SiO.sub.2, Al.sub.2 O.sub.3, Ta.sub.2 OI.sub.5, and MgO.
Claim 14
Dependent Claim
41 words
A gas sensor as claimed in claim 7, wherein said heater member has a heater layer which generates heat when power is supplied from an external power supply to said heater layer and an insulating layer formed on said heater layer.
References Cited (Backward Citations)
US4580439A
Cited
US5003812A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1996-10-04 | 1997-04-05 | 1997-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-10-04 | 2001-04-05 | 2001-10-05 | $3760.00 | Window Closed / Lapsed |
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