Patent US4038111A successfully refreshed from Google Patents.
US4038111A
Expired / Lapsed
US
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Method for diffusion of aluminium
Assignee: Silec Semi Conducteurs SA
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Filing: 1975-07-14
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Granted: 1977-07-26
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Expires: 1995-07-14
Abstract
Abstract The invention relates to a method for diffusing aluminium into a substrate by painting. According to this method, aluminium isopropylate is dissolved in ethoxyethanol at the maximum solubility. This solution is uniformly coated onto a substrate and a diffusion is carried out by placing this coated substrate into an open furnace. This invention is for manufacturing high voltage semiconductor devices.
Inventors
- 👤 Guy Henri Dumas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:52
CPC Classifications
H; H10; H10P; H10P32/00; H10P32/10; H10P32/14; H10P32/1408; H10P32/141; H10P32/17; H10P32/171; H10P32/19; H10P76/00; H10P76/40; H10P76/405; H10W; H10W74/00; H10W74/40; H10W74/47
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
88 words
A method of diffusing aluminium onto a semiconductor substrate comprising the steps of painting onto a semiconductor substrate a diffusable aluminium source comprising an organic aluminium compound: AlR.sub. 3 wherein R 3 is a C 1 - C 8 alkoxy group dissolved in a liquid composed of an alkoxyalkanol: R' -- R"OH wherein the alkoxy group R' has from 1 to 5 carbon atoms and the alkylene group R" has 1 to 5 carbon atoms; and thereafter heating the painted substrate diffusing the aluminium metal into the substrate.
Claim 2
Independent Claim
88 words
A method of diffusing aluminium onto a semiconductor substrate comprising the steps of painting onto a semiconductor substrate a diffusable aluminium source comprising an organic aluminium compound: AlR.sub. 3 wherein R 3 is a C 1 - C 8 alkoxy group dissolved in a liquid composed of an alkoxyalkanol: R' -- R"OH wherein the alkoxy group R' has from 1 to 5 carbon atoms and the alkylene group R" has 1 to 5 carbon atoms; and thereafter heating the painted substrate diffusing the aluminium metal into the substrate.
Claim 3
Dependent Claim
19 words
A method as in claim 1 wherein the mixture further comprises a glycol in order to increase its viscosity.
Claim 4
Dependent Claim
14 words
A method as in claim 1 wherein the organic aluminium compound is aluminium isopropoxide.
Claim 5
Dependent Claim
11 words
A method as in claim 1 wherein the alkoxyalkanol is ethoxyethanol.
Claim 6
Dependent Claim
47 words
A method for diffusing simultaneously aluminium and another doping agent wherein the aluminium source is prepared according to claim 1 and wherein a source of another dopant comprising also a mixture including a compound of this dopant is deposited over the layer acting as the aluminium source.
Claim 7
Dependent Claim
33 words
A method for diffusing simultaneously by painting two doping agents wherein the aluminium source according to claim 1 is mixed prior to its application onto the substrate with a source of another dopant.
Claim 8
Dependent Claim
40 words
A method as in claim 6 wherein the other dopant is boron and wherein the compound of the other dopant is boron oxide B 2 O 3 and wherein this compound B 2 O 3 is in suspension in ethoxyethanol.
Claim 9
Dependent Claim
28 words
A method as in claim 1 for effecting localized diffusion of aluminium further comprising the step of providing a masking layer made from silica coated with polycrystalline silicon.
Claim 10
Independent Claim
56 words
A method of diffusing aluminium onto a semiconductor substrate comprising the steps of applying to said substrate a diffusable aluminium source coating consisting essentially of aluminium isopropoxide substantially dissolved in ethoxyethanol and a glycol to increase viscosity of the coating; evaporating the solvent; and thereafter heating the thus coated substrate diffusing aluminium metal into the substrate.
Claim 11
Independent Claim
56 words
A method of diffusing aluminium onto a semiconductor substrate comprising the steps of applying to said substrate a diffusable aluminium source coating consisting essentially of aluminium isopropoxide substantially dissolved in ethoxyethanol and a glycol to increase viscosity of the coating; evaporating the solvent; and thereafter heating the thus coated substrate diffusing aluminium metal into the substrate.
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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) | 1980-07-25 | 1981-01-24 | 1981-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-25 | 1985-01-24 | 1985-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-25 | 1989-01-24 | 1989-07-26 | $7700.00 | Window Closed / Lapsed |