US5352623A
Expired / Lapsed
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Method for manufacturing a semiconductor device
Assignee: NEC Electronics Corp
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Filing: 1994-02-15
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Granted: 1994-10-04
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Expires: 2014-02-15
Abstract
Abstract A method for manufacturing a semiconductor device, wherein a thin film of tantalum oxide is formed as a dielectric film in a capacitor element, increases capacitance per unit area and reduces a leakage current in the capacitor element of DRAM memory cells. The method includes steps of forming a polysilicon film constituting a lower electrode of the capacitor element, removing a natural oxide film from the surface of the polysilicon film, nitriding the surface of the polysilicon by rapid thermal nitriding (RTN) using lamp-annealing, forming a tantalum oxide film, densifying and nitriding consecutively the tantalum oxide film, and forming an upper capacitor electrode thereon. The capacitor element formed by the method has a large capacitance per unit area Cs=13.8 fF/μm 2 .
Inventors
- 👤 Satoshi Kamiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:17
CPC Classifications
H; H10; H10B; H10B12/00; H10B12/01; H10B12/02; H10B12/03; H10B12/033; H10D; H10D1/00; H10D1/60; H10D1/68
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
83 words
A method for manufacturing a semiconductor device including steps of: forming a polysilicon film on an insulating film overlying a substrate; removing any natural oxide film from the surface of said polysilicon film; after said removing, nitriding the surface of said polysilicon film by lamp-heating to form a silicon nitride film; forming a tantalum oxide film on said silicon nitride film; densifying and nitriding consecutively said tantalum oxide film; after said densifying and nitriding, forming a conductive film on said tantalum oxide film.
Claim 2
Independent Claim
83 words
A method for manufacturing a semiconductor device including steps of: forming a polysilicon film on an insulating film overlying a substrate; removing any natural oxide film from the surface of said polysilicon film; after said removing, nitriding the surface of said polysilicon film by lamp-heating to form a silicon nitride film; forming a tantalum oxide film on said silicon nitride film; densifying and nitriding consecutively said tantalum oxide film; after said densifying and nitriding, forming a conductive film on said tantalum oxide film.
Claim 3
Dependent Claim
26 words
A method for manufacturing a semiconductor device as defined in claim 1, wherein said polysilicon film, tantalum oxide film and conductive film constitute a capacitor element.
Claim 4
Dependent Claim
19 words
A method for manufacturing a semiconductor device as defined in claim 2, wherein said semiconductor device is a DRAM.
Claim 5
Dependent Claim
35 words
A method for manufacturing a semiconductor device as defined in claim 1 wherein said removing of natural oxide film is conducted using at Least one of an anhydrous hydrogen fluoride and a diluted hydrofluoric acid.
Claim 6
Dependent Claim
31 words
A method for manufacturing a semiconductor device as defined in claim 1 wherein said nitriding of polysilicon film is conducted at a temperature between 800° and 1000° C. using ammonia gas.
Claim 7
Dependent Claim
35 words
A method for manufacturing a semiconductor device as defined in claim 1 wherein said forming of tantalum oxide film is conducted by a chemical vapor deposition using an organic tantalum compound as a source material.
Claim 8
Dependent Claim
38 words
A method for manufacturing a semiconductor device as defined claim 1 wherein said densifying of tantalum oxide film is conducted in an atmosphere containing at least one of oxygen (O 2 ) and nitrous oxide (N 2 O).
Claim 9
Dependent Claim
35 words
A method for manufacturing a semiconductor device as defined in claim 7 wherein said densifying of tantalum oxide film is conducted by heating using one of an electric furnace, lamp-heater, plasma-ion generator and combination thereof.
Claim 10
Dependent Claim
35 words
A method for manufacturing a semiconductor device as defined in claim 1 wherein said nitriding of tantalum oxide film is conducted by heating using plasma-ions of at least one of ammonia, nitrogen and nitrous oxide.
Claim 11
Dependent Claim
58 words
A method for manufacturing a semiconductor device as defined in claim 1 wherein at least one of said densifying and nitriding of tantalum oxide film is conducted by heating using plasma-ions at a temperature between a room temperature and 500° C., under a pressure between 0.1 and 10.0 Torr with an electric power between 50 and 500 W.
Claim 12
Dependent Claim
36 words
A method for manufacturing a semiconductor device as defined in claim 1 wherein said conductive layer is made of a material selected from a group consisting of titanium nitride, tungsten, molybdenum, tantalum, polysilicon and combination thereof.
References Cited (Backward Citations)
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| 3.5 Years (Year 4) | 1997-10-03 | 1998-04-04 | 1998-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-10-03 | 2002-04-04 | 2002-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-10-03 | 2006-04-04 | 2006-10-04 | $7700.00 | Window Closed / Lapsed |