US6109094A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and device for gas sensing
Assignee: Nordic Sensor Technologies AB
•
Filing: 1995-09-22
•
Granted: 2000-08-29
•
Expires: 2015-09-22
Abstract
Abstract A gas sensing device having a semiconductor substrate, wherein the semiconductor substrate is covered by an insulator layer, on which an intermediate layer is formed, and subsequently covered by a gas sensing catalytic layer, wherein the intermediate layer and the catalytic layer are made of different materials. The gas sensing device may optionally have dispersed between the insulator layer and the intermediate layer a catalytic metal layer. The gas sensing device provides improved stability and speed of response, even when used at high ambient temperatures, such as temperatures found in combustion systems. A method for making the gas sensing device is also disclosed.
Inventors
- 👤 Amir Baranzahi
- 👤 Ingemar Lundstrom
- 👤 Anita Lloyd Spetz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:05
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/0004; G01N33/0009; G01N33/0027; G01N33/0036; G01N33/005; G01N27/00; G01N27/26; G01N27/403; G01N27/414; G01N27/4141
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
112 words
A method of fabricating a gas sensor array comprising at least one gas sensitive semiconductor device including a suitably doped semiconductor substrate (1), comprising the steps of: comprising wide band-gap semiconductor material having a band-gap of at least 1.5 e.v.; providing a first layer semiconductor substrate (1); applying onto said first layer semiconductor substrate (1) by evaporation or sputtering, a second layer insulator layer (2); applying onto said second layer insulator layer (2) by evaporation or sputtering, a third layer mono- or multi-layer intermediate layer (4) which comprises a silicide; and applying onto said third layer mono- or multi-layer intermediate layer (4) by evaporation or sputtering, a fourth layer catalytic layer (5).
Claim 2
Independent Claim
112 words
A method of fabricating a gas sensor array comprising at least one gas sensitive semiconductor device including a suitably doped semiconductor substrate (1), comprising the steps of: comprising wide band-gap semiconductor material having a band-gap of at least 1.5 e.v.; providing a first layer semiconductor substrate (1); applying onto said first layer semiconductor substrate (1) by evaporation or sputtering, a second layer insulator layer (2); applying onto said second layer insulator layer (2) by evaporation or sputtering, a third layer mono- or multi-layer intermediate layer (4) which comprises a silicide; and applying onto said third layer mono- or multi-layer intermediate layer (4) by evaporation or sputtering, a fourth layer catalytic layer (5).
Claim 3
Dependent Claim
36 words
A method of fabricating a gas sensor array according to claim 1, further comprising the step of applying by evaporation or sputtering, a catalytic metal layer (3) before applying said mono- or multi-layer intermediate layer (4).
Claim 4
Dependent Claim
14 words
The method according to claim 1, wherein the insulator layer (2) comprises an oxide.
Claim 5
Dependent Claim
25 words
The method according to claim 1, wherein the wide band-gap semiconductor material comprises a member selected from the group consisting of silicon carbide and diamond.
Claim 6
Dependent Claim
17 words
The method according to claim 1, wherein said intermediate layer (4) is subjected to an annealing step.
Claim 7
Dependent Claim
19 words
The method of claim 5, wherein the annealing step is carried out a temperature of at least 500° C.
Claim 8
Dependent Claim
14 words
The method according to claim 1, wherein said intermediate layer (4) comprises a silicide.
Claim 9
Dependent Claim
14 words
The method according to claim 7, wherein the intermediate layer (4) comprises tantalum silicide.
Claim 10
Dependent Claim
129 words
A gas sensing array comprising at least one sensing device, wherein said sensing device comprises: a first layer semiconductor substrate (1); comprising wide band-gap semiconductor material having a band-gap of at least 1.5 e.v.; a second layer insulator layer (2) disposed on said first layer semiconductor substrate (1); a third layer intermediate layer (4) comprising a silicide, and disposed on said second layer insulator layer (2); and a fourth layer catalytic layer (5) disposed on said third layer intermediate layer (4); wherein said fourth layer catalytic layer (5), when in contact with a gas to be measured, changes an electric field outside said first layer semiconductor substrate (1); and said mono- or multi-layers of the third layer intermediate layer (4) are different from said fourth layer catalytic layer (5).
Claim 11
Dependent Claim
129 words
A gas sensing array comprising at least one sensing device, wherein said sensing device comprises: a first layer semiconductor substrate (1); comprising wide band-gap semiconductor material having a band-gap of at least 1.5 e.v.; a second layer insulator layer (2) disposed on said first layer semiconductor substrate (1); a third layer intermediate layer (4) comprising a silicide, and disposed on said second layer insulator layer (2); and a fourth layer catalytic layer (5) disposed on said third layer intermediate layer (4); wherein said fourth layer catalytic layer (5), when in contact with a gas to be measured, changes an electric field outside said first layer semiconductor substrate (1); and said mono- or multi-layers of the third layer intermediate layer (4) are different from said fourth layer catalytic layer (5).
Claim 12
Dependent Claim
52 words
A gas sensing array according to claim 9, further comprising a catalytic metal layer (3) disposed between said second layer insulator layer (2) and said third layer intermediate layer (4), wherein said third layer intermediate layer (4) is different from said catalytic metal layer (3) and said fourth layer catalytic layer (5).
Claim 13
Dependent Claim
43 words
The gas sensing array according to claim 9, wherein said layers form a field effect structure selected from the group consisting of: a field effect transistor, a metal-insulator-semiconductor capacitor, a metal thin insulator semiconductor diode, a Schottky barrier device and a tunneling device.
Claim 14
Dependent Claim
16 words
The gas sensing array according to claim 11, wherein the insulator layer (2) comprises an oxide.
Claim 15
Dependent Claim
40 words
The gas sensing array according to claim 9, wherein the catalytic layer (5) comprises a member selected from the group consisting of: a catalytic metal, a catalytic alloy, a catalytic oxide, a catalytic ceramic compound and a catalytic polymer compound.
Claim 16
Dependent Claim
25 words
The gas sensing array according to claim 9, wherein the semiconductor material comprises a member selected from the group consisting of silicon carbide and diamond.
Claim 17
Dependent Claim
19 words
The gas sensing array according to claim 9, wherein the intermediate layer (4) is subjected to an annealing step.
Claim 18
Dependent Claim
16 words
The gas sensing array according to claim 9, wherein said intermediate layer (4) comprises a silicide.
Claim 19
Dependent Claim
63 words
The method according to claim 1 further comprising the step of applying an insulator layer (2) onto said semiconductor substrate (1), before the application of additional layers, wherein the combined layers form a field effect device selected from the group consisting of: a field effect transistor, a metal-insulator-semiconductor capacitor, a metal thin insulator semiconductor diode, a Schottky barrier device and a tunneling device.
Claim 20
Dependent Claim
38 words
The method according to claim 1, wherein the catalytic layer (5) comprises a member selected from the group consisting of a catalytic metal, a catalytic alloy, a catalytic oxide, a catalytic ceramic compound and a catalytic polymer compound.
Claim 21
Dependent Claim
23 words
The gas sensing array according to claim 15, wherein the annealing step is carried out at a temperature of at least 500° C.
Claim 22
Dependent Claim
16 words
The gas sensing array according to claim 16, wherein said intermediate layer (4) comprises tantalum silicide.
Claim 23
Dependent Claim
22 words
A gas sensing array according to claim 9, wherein the intermediate layer (4) is an electrically conductive contact for the semiconductor device.
Claim 24
Dependent Claim
15 words
The gas sensing array according to claim 9, wherein the intermediate layer (4) is non-catalytic.
References Cited (Backward Citations)
US3699803A
Cited
US4322383A
Cited
US4337476A
Cited
CH665908A5
Cited
US4816888A
Cited
US4931851A
Cited
US4897628A
Cited
US4911892A
Cited
US4885929A
Cited
US4875083A
Cited
US5250170A
Cited
US5147523A
Cited
EP0488352A2
Cited
US5251470A
Cited
DE4223432A1
Cited
US5154514A
Cited
US5273779A
Cited
US5401470A
Cited
US5285084A
Cited
US5323022A
Cited
US5384470A
Cited
WO1994027139A1
Cited
EP0635717A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-08-29 | 2004-02-28 | 2004-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-08-29 | 2008-02-28 | 2008-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-08-29 | 2012-02-28 | 2012-08-29 | $7700.00 | Window Closed / Lapsed |