US4540607A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Selective LPCVD tungsten deposition by the silicon reduction method
Assignee: AMI Semiconductor Inc
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Filing: 1983-08-08
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Granted: 1985-09-10
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Expires: 2003-08-08
Abstract
Abstract A method is described for treating the surface of a field-effect transistor or a Schottky barrier diode. A polysilicon surface of a gate region of an FET or a single crystalline silicon surface of a Schottky barrier diode may be treated with a low-power argon-plasma for a relatively short period of time to enhance nucleation sites on the surface of the polysilicon or single crystalline silicon. A layer of tungsten or molybdenum may be selectively deposited on the surface of the polysilicon or single crystalline silicon by chemical-vapor deposition through silicon reduction of tungsten hexafluoride or molybdenum hexafluoride.
Inventors
- 👤 Kuey-Yeou Tsao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:50
CPC Classifications
H; H10; H10P; H10P70/00; H10P70/10; H10P70/12; C; C23; C23C; C23C16/00; C23C16/02; C23C16/0227; C23C16/0245; H10D; H10D64/00; H10D64/01; H10D64/012; H10D64/0121; H10P70/20; H10P70/23; H10P70/234
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
38 words
A method of treating polycrystalline and single crystalline silicon surfaces having nucleation sites thereon, comprising the step of: preparing said surface by exposing said surface to an inert plasma to induce more uniform nucleation sites on said surface.
Claim 2
Independent Claim
38 words
A method of treating polycrystalline and single crystalline silicon surfaces having nucleation sites thereon, comprising the step of: preparing said surface by exposing said surface to an inert plasma to induce more uniform nucleation sites on said surface.
Claim 3
Dependent Claim
24 words
A method of preparing surfaces as recited in claim 1, wherein said polysilicon surface is exposed to an argon-plasma for two to thirty minutes.
Claim 4
Dependent Claim
28 words
A method of treating said surfaces as recited in claim 1, wherein said plasma is an argon plasma in a power range of 2 W to 50 W.
Claim 5
Dependent Claim
65 words
A method of treating surfaces as recited in claim 1, further comprising the step of: selectively depositing up to 1,000 angstroms of tungsten by chemical-vapor deposition on said surface according to the reaction 2WF.sub.6 +3Si→2W+3SiF.sub.4 wherein a thin layer of said surface is consumed during deposition to produce SiF 4 and tungsten remains on said surface, said depositing step being performed after said preparing step.
Claim 6
Dependent Claim
21 words
A method of treating surfaces as recited in claim 4, wherein said chemical-vapor deposition lasts from two minutes to thirty minutes.
Claim 7
Dependent Claim
28 words
A method of treating surfaces as recited in claim 4, wherein said temperature of said surface during said deposition step is in the range of 300° C.-550° C.
Claim 8
Dependent Claim
29 words
A method of treating surfaces as recited in claim 4, wherein the thickness of tungsten deposited on said surface during said depositing step is up to 1000 angstroms thick.
Claim 9
Dependent Claim
20 words
A method of treating surfaces as recited in claim 4, wherein said depositing step is performed in an argon atmosphere.
Claim 10
Dependent Claim
55 words
A method of treating surfaces as recited in claim 1, further comprising the step of: selectively depositing molybdenum by chemical-vapor deposition on said surfaces according to the following reaction 2MoF.sub.6 +3Si→2Mo+3SiF.sub.4 ↑ wherein a thin layer of said surface is consumed during said chemical-vapor deposition step, said depositing step being performed after said preparing step.
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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) | 1988-09-09 | 1989-03-11 | 1989-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-09 | 1993-03-11 | 1993-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-09 | 1997-03-11 | 1997-09-10 | $7700.00 | Window Closed / Lapsed |