US4144634A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fabrication of gallium arsenide MOS devices
Assignee: AT&T Inc
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Filing: 1977-06-28
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Granted: 1979-03-20
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Expires: 1997-06-28
Abstract
Abstract A method of fabricating gallium arsenide MOS devices with improved stoichiometric and electrical properties is disclosed. The device includes a gallium arsenide substrate overlaid with a native oxide and an aluminum oxide layer. The device is fabricated using a plasma oxidizing process.
Inventors
- 👤 Chuan C. Chang
- 👤 Robert P. H. Chang
- 👤 James J. Coleman
- 👤 Tan T. Sheng
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 00:51
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/69; H10P14/692; H10P14/6938; H10P14/6939; H10P14/69391; H10D; H10D64/00; H10D64/01; H10D64/013; H10D64/01358; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6314; H10P14/6319; H10P14/65; H10P14/6516; H10P14/6529; Y; Y10; Y10S; Y10S148/00; Y10S148/003; Y10S148/043; Y10S148/118
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
178 words
A method comprising (a) depositing an aluminum layer of thickness less than 400 Angstroms on a doped gallium arsenide substrate; (b) placing the substrate in an oxygen environment comprising oxygen at a pressure of less than 10 -3 Torr; (c) directing a beam comprising essentially electrons of density between 10 8 electrons/cm 3 and 10 12 electrons/cm 3 toward the aluminum layer in part by means of a magnetic field greater than 50 Gauss; (d) biasing the substrate between 0.2 and 500 volts positive with respect to the source of electrons whereby a structure is formed with an aluminum oxide layer less than 400 Angstroms thick over a native oxide between 500 and 4000 Angstroms thick; and (e) annealing the structure; (f) depositing a metal electrode on the structure whereby a MOS device with a breakdown strength of greater than ±4 × 10 6 volts/cm, an asymptotic slope in both the inversion and accumulation regions with an absolute value of less than 0.02pF/V, and a surface state density less than 1 × 10 11 /cm 2 is formed.
Claim 2
Independent Claim
178 words
A method comprising (a) depositing an aluminum layer of thickness less than 400 Angstroms on a doped gallium arsenide substrate; (b) placing the substrate in an oxygen environment comprising oxygen at a pressure of less than 10 -3 Torr; (c) directing a beam comprising essentially electrons of density between 10 8 electrons/cm 3 and 10 12 electrons/cm 3 toward the aluminum layer in part by means of a magnetic field greater than 50 Gauss; (d) biasing the substrate between 0.2 and 500 volts positive with respect to the source of electrons whereby a structure is formed with an aluminum oxide layer less than 400 Angstroms thick over a native oxide between 500 and 4000 Angstroms thick; and (e) annealing the structure; (f) depositing a metal electrode on the structure whereby a MOS device with a breakdown strength of greater than ±4 × 10 6 volts/cm, an asymptotic slope in both the inversion and accumulation regions with an absolute value of less than 0.02pF/V, and a surface state density less than 1 × 10 11 /cm 2 is formed.
Claim 3
Dependent Claim
13 words
The method of claim 1 where the aluminum layer is deposited by evaporation.
Claim 4
Dependent Claim
20 words
The method of claim 1 where the MOS device is annealed for a time period between 30 and 60 minutes.
Claim 5
Dependent Claim
13 words
The method of claim 1 where the electrons are formed in a plasma.
Claim 6
Dependent Claim
16 words
The method of claim 1 where the structure is annealed in hydrogen at approximately one atmosphere.
References Cited (Backward Citations)
US4062747A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-03-19 | 1982-09-18 | 1983-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-03-19 | 1986-09-18 | 1987-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-03-19 | 1990-09-18 | 1991-03-20 | $7700.00 | Window Closed / Lapsed |