US5238849A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of fabricating semiconductor device
Assignee: NEC Electronics Corp
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Filing: 1991-08-30
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Granted: 1993-08-24
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Expires: 2011-08-30
Abstract
Abstract A bipolar transistor having a silicon oxide film having a stoichiometric composition ratio of silicon to oxygen controlled to 1 to 2 formed at the boundary between a monocrystalline layer and a polycrystalline layer. In fabrication, a natural oxidized film formed on the surface of an intrinsic base region of a single-crystal is removed in an ultrahigh-vacuum chamber. Subsequently, oxygen ions are supplied to the surface of the base region at room temperature to form a silicon oxide film. Further, silicon molecular beams are supplied in the same chamber to form the polycrystalline silicon layer. The current gain factor h FE of the bipolar transistor thus formed can be greatly improved.
Inventors
- 👤 Fumihiko Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 20:50
CPC Classifications
H; H10; H10D; H10D10/00; H10D10/01; H10D10/051; H10P; H10P32/00; H10P32/10; H10P32/14; H10P32/1408; H10P32/1414; H10P32/17; H10P32/171; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6306; H10P14/6308; H10P14/6309; H10P14/65; H10P14/6502; H10P14/6504; H10P14/69; H10P14/692; H10P14/6921; H10P14/69215; Y; Y10; Y10S; Y10S148/00; Y10S148/017; Y10S148/118; Y10S148/124; Y10S438/00; Y10S438/974
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
99 words
A method of fabricating a semiconductor bipolar transistor comprising: cleaning a single-crystal silicon surface within an opening formed in an insulating film on a first single-crystal silicon island region having a first conductivity type selectively formed in a single-crystal silicon substrate; forming a silicon oxide film on said cleaned silicon surface by applying only pure oxygen ions supplied into a vacuum chamber, said oxide film being formed at room temperature, said only pure oxygen ions being produced by electron cyclotron resonance ECR; and depositing, in said vacuum chamber, a poly or amorphous silicon layer doped with or without impurities.
Claim 2
Independent Claim
99 words
A method of fabricating a semiconductor bipolar transistor comprising: cleaning a single-crystal silicon surface within an opening formed in an insulating film on a first single-crystal silicon island region having a first conductivity type selectively formed in a single-crystal silicon substrate; forming a silicon oxide film on said cleaned silicon surface by applying only pure oxygen ions supplied into a vacuum chamber, said oxide film being formed at room temperature, said only pure oxygen ions being produced by electron cyclotron resonance ECR; and depositing, in said vacuum chamber, a poly or amorphous silicon layer doped with or without impurities.
Claim 3
Independent Claim
68 words
A method of fabricating a semiconductor device comprising the steps of: forming a base region in a collector region; cleaning a surface of said base region; forming a silicon oxide film at room temperature by supplying only pure oxygen ions in a plasma produced by an electron cyclotron resonance ECR to the cleaned surface of said base region; and forming a polysilicon layer on said silicon oxide film.
Claim 4
Independent Claim
68 words
A method of fabricating a semiconductor device comprising the steps of: forming a base region in a collector region; cleaning a surface of said base region; forming a silicon oxide film at room temperature by supplying only pure oxygen ions in a plasma produced by an electron cyclotron resonance ECR to the cleaned surface of said base region; and forming a polysilicon layer on said silicon oxide film.
Claim 5
Independent Claim
89 words
A method of fabricating a bipolar transistor comprising: a first step of selectively forming a silicon oxide film on a monocrystalline silicon area by supplying only a pure oxygen ion gas produced by electron cyclotron resonance ECR at room temperature onto a single-crystalline silicon area in an atmosphere of the vacuum degree of 2×10 -5 Torr; and a second step of depositing a polycrystalline silicon film on said silicon oxide film whereby said monocrystalline silicon area constitutes an emitter region and said polycrystalline silicon film constitutes an emitter electrode.
Claim 6
Independent Claim
89 words
A method of fabricating a bipolar transistor comprising: a first step of selectively forming a silicon oxide film on a monocrystalline silicon area by supplying only a pure oxygen ion gas produced by electron cyclotron resonance ECR at room temperature onto a single-crystalline silicon area in an atmosphere of the vacuum degree of 2×10 -5 Torr; and a second step of depositing a polycrystalline silicon film on said silicon oxide film whereby said monocrystalline silicon area constitutes an emitter region and said polycrystalline silicon film constitutes an emitter electrode.
Claim 7
Dependent Claim
37 words
A method of fabricating a bipolar transistor according to claim 3, wherein said ECR oxidation is performed for a period of time ranging from several seconds to several tens seconds at a substrate temperature of room temperature.
Claim 8
Dependent Claim
20 words
A method of fabricating a bipolar transistor according to claim 4, wherein said ECR oxidation is performed for 15 seconds.
Claim 9
Dependent Claim
33 words
A method of fabricating a bipolar transistor according to claim 3, further comprising the steps of, before the first step, exposing said monocrystalline silicon area and removing a natural oxidized film thus formed.
Claim 10
Dependent Claim
38 words
A method of fabricating a bipolar transistor according to claim 6, wherein said natural oxidized film is removed by heat treatment for 10 minutes at 850° C. in an atmosphere of the vacuum degree of 5×10 -8 Torr.
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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) | 1996-08-23 | 1997-02-22 | 1997-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-23 | 2001-02-22 | 2001-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-23 | 2005-02-22 | 2005-08-24 | $7700.00 | Window Closed / Lapsed |