US4206540A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Schottky device and method of manufacture using palladium and platinum intermetallic alloys and titanium barrier
Assignee: Infineon Technologies Americas Corp
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Filing: 1978-06-02
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Granted: 1980-06-10
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Expires: 1998-06-02
Abstract
Abstract A schottky diode and process of manufacture therefor is disclosed wherein a schottky junction is formed between a high work function metal, typically molybdenum, and a single crystal intermetallic alloy of either palladium or platinum with silicon. The intermetallic alloy is formed by sintering palladium or platinum with silicon at the surface of an epitaxial silicon layer, and then removing, by etching, all of the silicide which is formed. The intermetallic layer remains after the etching process. When using platinum as the metal to form to silicide, the platinum is sheathed with molybdenum before sintering. A titanium layer is placed between the surface of the high work function metal and the outer conductive layers used to permit soldering of the finished wafer or chip in place to avoid degradation of the junction during solder-down.
Inventors
- 👤 Herbert J. Gould
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 02:01
CPC Classifications
H; H10; H10D; H10D8/00; H10D8/60; H10D64/00; H10D64/01; H10D64/012; H10D64/0121; H10D64/60; H10D64/64; Y; Y10; Y10S; Y10S148/00; Y10S148/139
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
87 words
The process of manufacture of a schottky device comprising the steps of depositing a first metal selected from the group consisting of palladium and platinum on the surface of a silicon wafer, sintering said first metal into said surface of said silicon wafer, completely removing all traces of said first metal and any silicides thereof from said surface such that the exposed surface exhibits a sharp knee reverse voltage characteristic when engaged by a tungsten probe, and depositing a high work function metal on said exposed surface.
Claim 2
Dependent Claim
87 words
The process of manufacture of a schottky device comprising the steps of depositing a first metal selected from the group consisting of palladium and platinum on the surface of a silicon wafer, sintering said first metal into said surface of said silicon wafer, completely removing all traces of said first metal and any silicides thereof from said surface such that the exposed surface exhibits a sharp knee reverse voltage characteristic when engaged by a tungsten probe, and depositing a high work function metal on said exposed surface.
Claim 3
Dependent Claim
37 words
The process of claim 1 which includes the further steps of depositing a titanium layer atop said high work function metal and depositing a contact metal atop said titanium layer and soldering said device into a housing.
Claim 4
Dependent Claim
28 words
The process of claim 1 or 2 wherein said first metal and the silicides thereof are removed by etching in aqua regia for an extended period of time.
Claim 5
Dependent Claim
27 words
The process of claim 1 or 2 wherein said first metal is palladium, and wherein said surface is made free of any trace of Pd 2 Si.
Claim 6
Dependent Claim
25 words
The process of claim 1 or 2 wherein said first metal is platinum, and wherein said surface is made free of any trace of PtSi.
Claim 7
Dependent Claim
15 words
The process of claim 5, wherein said platinum metal is covered with molybdenum during sintering.
Claim 8
Dependent Claim
68 words
The process of manufacture of a schottky device comprising the steps of depositing palladium on the surface of a silicon wafer, sintering said palladium into said surface of said silicon wafer, completely removing all traces of said palladium and any silicides thereof from said surface of said silicon wafer, and depositing a high work function metal on said surface after all silicides of palladium have been removed therefrom.
Claim 9
Dependent Claim
68 words
The process of manufacture of a schottky device comprising the steps of depositing palladium on the surface of a silicon wafer, sintering said palladium into said surface of said silicon wafer, completely removing all traces of said palladium and any silicides thereof from said surface of said silicon wafer, and depositing a high work function metal on said surface after all silicides of palladium have been removed therefrom.
Claim 10
Dependent Claim
25 words
The process of claim 7 wherein said palladium and the silicides thereof are removing by etching in aqua regia for an extended period of time.
Claim 11
Dependent Claim
64 words
The process of manufacture of a schottky device comprising the steps of depositing platinum on the surface of a silicon wafer, sintering said platinum into said surface of said silicon wafer, removing all traces of said platinum and any silicides thereof from said surface, and depositing a high work function metal on said surface after all of the platinum silicides have been removed therefrom.
Claim 12
Dependent Claim
64 words
The process of manufacture of a schottky device comprising the steps of depositing platinum on the surface of a silicon wafer, sintering said platinum into said surface of said silicon wafer, removing all traces of said platinum and any silicides thereof from said surface, and depositing a high work function metal on said surface after all of the platinum silicides have been removed therefrom.
Claim 13
Dependent Claim
24 words
The process of claim 9 wherein said platinum and the silicides thereof are removed by etching in aqua regia for an extended period time.
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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) | 1983-06-10 | 1983-12-10 | 1984-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-06-10 | 1987-12-10 | 1988-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-06-10 | 1991-12-10 | 1992-06-10 | $7700.00 | Window Closed / Lapsed |