US3616401A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sputtered multilayer ohmic molygold contacts for semiconductor devices
Assignee: Texas Instruments Inc
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Filing: 1966-06-30
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Granted: 1971-10-26
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Expires: 1986-06-30
Abstract
Abstract Disclosed are methods for depositing multilayer ohmic contacts upon a substrate of semiconductor material disposed within a low pressure chamber; such including for example the particular features of upward sputtering of the various metal films including deposition of a thin layer of molybdenum directly on initially formed integral areas of platinum silicide, followed by simultaneous sputtering of platinum with gold utilizing a sputtering cathode composed of platinum and gold, with the addition of hydrogen into an inert sputtering atmosphere to eliminate undesireable formation of oxides. This invention provides improved adhesion of the sputtered metal films to the semiconductor surface and the silicon oxide, and provides the formation of the metal film which is substantially free of pin holes and which has substantially uniform resistivity.
Inventors
- 👤 James A Cunningham
- 👤 Coy D Orr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 06:50
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/40; H10D; H10D99/00; H10P; H10P95/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
56 words
The method of claim 1 wherein prior to the formation of said sintered platinum silicide layer, the step of diffusing collector, base and emitter regions having portions surfacing at said one major face is included for producing transistors having active regions thereof selectively connected to said opposite conductivity regions and for selectively providing external contact members.
Claim 2
Dependent Claim
20 words
The method of claim 1 wherein said inert gas is approximately 90 percent argon and 10 percent hydrogen by volume.
Claim 3
Dependent Claim
26 words
The method of claim 1 wherein said second cathode and said second thin film are each approximately 95 percent gold and 5 percent platinum by weight.
Claim 4
Independent Claim
300 words
A method for providing ohmic contacts to semiconductor devices of the type having a plurality of opposite conductivity type regions at one major face of a silicon semiconductor wafer, said wafer having an insulating coating upon said one major face and having apertures in said insulating coating exposing selected portions of said regions, said wafer being disposed within a low pressure chamber, comprising the following steps: a. providing a sintered platinum silicide layer upon each of said exposed portions of said regions; b. directing a flow of gas into said chamber, said flow being composed of approximately 90 percent argon and 10 percent hydrogen by Volume; c. producing a first glow discharge of positively charged argon ions between a first pair of spaced electrodes located within said chamber, said first glow discharge being beneath said one major face of said wafer; d. applying a voltage to a first cathode comprised of molybdenum to attract said positively charged argon ions to said first cathode with sufficient energy to cause a sputtering of a first thin film comprised of molybdenum upon said insulating coating and said exposed portions of said regions; e. producing a second glow discharge of positively charged argon ions between a second pair of spaced electrodes located within said chamber, said second glow discharge being beneath said one major face of said wafer; f. applying a voltage to a second cathode comprised of approximately 5 percent platinum and 95 percent gold by weight to attract said positively charged argon ions of said second glow discharge with sufficient energy to said second cathode to cause sputtering of a second thin film comprised of approximately 5 percent platinum and 95 percent gold by weight upon said first thin film; and g. evaporating a layer of gold upon said second thin film.
Claim 5
Dependent Claim
36 words
The method of claim 5 and further including the step of photochemically removing selected portions of said first thin film, said second thin film and said gold layers for selectively connecting said regions of said substrate.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-25 | 1975-04-26 | 1975-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-25 | 1979-04-26 | 1979-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-25 | 1983-04-26 | 1983-10-26 | $7700.00 | Window Closed / Lapsed |