Patent US4780428A successfully refreshed from Google Patents.
US4780428A
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Mosfet semiconductor device and manufacturing method thereof
Assignee: Sharp Corp
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Filing: 1987-06-10
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Granted: 1988-10-25
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Expires: 2007-06-10
Abstract
Abstract A method of forming a gate insulating film on a MOSFET. After a SiO 2 film is formed by thermal oxidation as a gate insulating film on a MOSFET, the SiO 2 film is removed by selective etching from the surface area other than MOSFET region, and an oxygen doped semi-insulating polycrystalline silicon film is deposited thereon. Then, a silicon nitride layer is deposited and a SiO 2 film is formed by CVD method on the surface area other than the MOSFET region.
Inventors
- 👤 Yukinori Nakakura
- 👤 Nobuyuki Kato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:08
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/013; H10D64/01302; H10D64/01332; H10D64/01336; H10D64/01344; H10D64/60; H10D64/66; H10D64/68; H10D64/681; H10D64/685; H10D64/693; H10D64/01346
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
75 words
A method of forming a MOSFET gate insulating film comprising the steps of: forming a first SiO 2 film as a gate insulating film on a MOSFET surface; removing the first SiO 2 film from the surface area other than the MOSFET region; depositing an oxygen doped semi-insulating polycrystalline silicon film; removing the oxygen doped semi-insulating polycrystalline silicon film from the MOSFET region; and depositing a silicon nitride film and a second SiO 2 film.
Claim 2
Independent Claim
75 words
A method of forming a MOSFET gate insulating film comprising the steps of: forming a first SiO 2 film as a gate insulating film on a MOSFET surface; removing the first SiO 2 film from the surface area other than the MOSFET region; depositing an oxygen doped semi-insulating polycrystalline silicon film; removing the oxygen doped semi-insulating polycrystalline silicon film from the MOSFET region; and depositing a silicon nitride film and a second SiO 2 film.
Claim 3
Dependent Claim
16 words
The method of claim 1, wherein the first SiO 2 film is formed by thermal oxidation.
Claim 4
Dependent Claim
24 words
The method of claim 1, wherein the first SiO 2 film and the oxygen doped semi-insulating polycrystalline silicon film are removed by selective etching.
Claim 5
Dependent Claim
22 words
The method of claim 3, wherein the oxygen doped semi-insulating polycrystalline silicon film is selectively removed by CF 4 gas plasma etching.
Claim 6
Dependent Claim
29 words
The method of claim 1, wherein the oxygen doped semi-insulating polycrystalline silicon film, the silicon nitride film and the second SiO 2 film are formed by chemical vapor deposition.
Claim 7
Dependent Claim
27 words
The method of claim 5, wherein the oxygen doped semi-insulating polycrystalline silicon film and the silicon nitride film are formed by chemical vapor deposition under reduced pressure.
Claim 8
Dependent Claim
20 words
The method of claim 1, further comprising the step of removing the second SiO 2 film from the MOSFET region.
Claim 9
Dependent Claim
19 words
The method of claim 7, further comprising the step of removing the silicon nitride film from the MOSFET region.
Claim 10
Dependent Claim
20 words
The method of claim 8, wherein the second SiO 2 film and the silicon nitride film are removed by etching.
Claim 11
Dependent Claim
15 words
The method of claim 9, wherein the silicon nitride film is removed by plasma etching.
Claim 12
Dependent Claim
17 words
The method of claim 9, wherein the second SiO 2 film is removed by photoetching and/or wet-etching.
Claim 13
Dependent Claim
25 words
The method of claim 7, wherein the silicon nitride film layering on the first SiO 2 film functions as the gate insulating film in combination.
Claim 14
Dependent Claim
26 words
The method of claim 1, wherein the oxygen doped semi-insulating polycrystalline silicon film is formed by depositing a two-layer polysilicon film or a multilayer polysilicon film.
Claim 15
Dependent Claim
28 words
The method of claim 1, wherein the silicon nitride film and the second SiO 2 are deposited at least on the surface area other than the MOSFET region.
Claim 16
Dependent Claim
26 words
The method of claim 1, wherein the silicon nitride film is formed for electrically separating the second SiO 2 film from the first SiO 2 film.
Claim 17
Dependent Claim
17 words
The method of claim 1, wherein the second SiO 2 film is formed for preventing insulating breakdown.
Claim 18
Dependent Claim
56 words
The method of claim 1, wherein the first SiO 2 film is reduced in thickness by less than 5 percent from the initial thickness of the first SiO 2 film after the oxygen doped semi-insulating polycrystalline film is selectively removed by CF 4 gas plasma etching and the silicon nitride film is removed by plasma etching.
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