US3664874A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tungsten contacts on silicon substrates
Assignee: National Aeronautics and Space Administration
•
Filing: 1969-12-31
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Granted: 1972-05-23
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Expires: 1989-12-31
Abstract
Abstract Disclosed are a process whereby tungsten contact electrodes are formed on doped silicon substrates, such as integrated circuit chips and solar cells, and the resultant products. The method comprises depositing elemental tungsten on contact areas of doped silicon semiconductor devices, and thereafter processing the silicon devices to induce a chemical reaction between the tungsten and the silicon. The resulting tungsten contact electrodes thereby include a transition region at the interface of the tungsten electrode and silicon device comprising tungstensilicon compounds which are physically and chemically bonded to, and form an integral part of, both the tungsten electrode material and the silicon semiconductor material. A lead is bonded directly to the tungsten electrode.
Inventors
- 👤 Joseph Epstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:43
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/0112; H10F; H10F77/00; H10F77/20; H10F77/206; H10F77/211; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12389; Y10T428/12396; Y10T428/12486; Y10T428/12493; Y10T428/12674; Y10T428/12771; Y10T428/12806; Y10T428/12826; Y10T428/1284
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
23 words
The method of claim 1 wherein said contact electrode is a metallization electrode and said silicon substrate is a silicon integrated circuit substrate.
Claim 2
Dependent Claim
22 words
The method of claim 1 wherein said contact electrode is a collector electrode and said silicon substrate is a silicon solar cell.
Claim 3
Dependent Claim
20 words
The method of claim 1 comprising the further step of attaching an electrical lead directly to said deposited elemental tungsten.
Claim 4
Dependent Claim
54 words
The method of claim 1, wherein said elemental tungsten is deposited on said unmasked areas of said substrate at a temperature in excess of 3,000* C., while simultaneously heating said substrate to a temperature in excess of 1,300* C. and permitting said deposition to occur over a period of from 5 to 20 minutes.
Claim 5
Dependent Claim
28 words
The method of claim 1 wherein said heating step is an annealing function performed at a temperature between 1,350* and 1,385* C. for between 5 and 20 minutes.
Claim 6
Dependent Claim
83 words
A tungsten contact electrode for a silicon substrate comprising a tungsten electrode situated on a contact area of said silicon substrate to form an interface between said tungsten electrode and said silicon substrate, a gradation of tungsten silicide compounds of differing molecular weights in the region of said interface, said tungsten silicide compounds being physically and chemically bonded to, and forming an integral part oF, both said tungsten electrode and said silicon substrate, and an electrical lead attached directly to said tungsten electrode.
Claim 7
Dependent Claim
31 words
A tungsten contact electrode for a silicon substrate as defined in claim 7 wherein said contact electrode is a metallization electrode and said silicon substrate is a silicon integrated circuit substrate.
Claim 8
Dependent Claim
30 words
A tungsten contact electrode for a silicon substrate as defined in claim 7 wherein said contact electrode is a collector electrode and said silicon substrate is a silicon solar cell.
Claim 9
Independent Claim
103 words
A method of forming a tungsten contact electrode on a passivated silicon substrate having a mask thereon to define a contact electrode configuration and having been prepared to receive said tungsten contact electrode, comprising depositing elemental tungsten in said contact electrode configuration on said substrate and annealing said substrate with said deposited elemental tungsten at temperatures in excess of 1,300* C. for a period sufficiently long to form a gradation of tungsten silicide compounds of differing molecular weights, said tungsten silicide compounds being physically and chemically bonded to, and forming an integral part of, both said deposited elemental tungsten and said silicon 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) | 1975-05-23 | 1975-11-22 | 1976-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-23 | 1979-11-22 | 1980-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-23 | 1983-11-22 | 1984-05-23 | $7700.00 | Window Closed / Lapsed |