US5032541A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing a semiconductor device including a Schottky gate
Assignee: Mitsubishi Electric Corp
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Filing: 1989-08-21
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Granted: 1991-07-16
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Expires: 2009-08-21
Abstract
Abstract A method of producing a semiconductor device includes etching a recessed aperture in a substrate, forming a gate electrode in the aperture, burying the gate electrode with resist, etching the resist to expose the gate electrode, depositing a high conductivity metal on the gate electrode, and forming ohmic electrodes on opposite sides of the gate electrode by a series of processing steps.
Inventors
- 👤 Shinichi Sakamoto
- 👤 Takuji Sonoda
- 👤 Kazuo Hayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:23
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/061; H10D30/0612; H10D64/00; H10D64/01; H10D64/011; H10D64/012; H10D64/0124; H10D64/0125
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
220 words
A method of producing a semiconductor device comprising: depositing an inert spacer on a surface of a semiconductor substrate; depositing a first mask on the spacer; forming an aperture in the first mask; etching a recess in the surface of the substrate; depositing a first metal in the recess as a gate electrode and on the first mask; removing unneeded first metal by removing the first mask; burying the gate electrode by applying a second mask to the surface of the substrate and the spacer; etching the second mask to expose the gate electrode; depositing a second metal having a relatively high electrical conductivity on the gate electrode and second mask; applying a third mask having a larger thickness than that of the second mask on the second metal opposite the gate electrode; etching the second metal where it is not covered by the third mask and at the side walls of the layer of the second metal to produce a stripe of the second metal having a desired width; removing the third mask and the spacer except opposite the second mask; depositing a third metal to form ohmic electrodes at opposite sides of the gate electrode using the second mask for self-alignment of the ohmic electrodes; and annealing the gate electrode and the second metal to improve their adhesion.
Claim 2
Independent Claim
220 words
A method of producing a semiconductor device comprising: depositing an inert spacer on a surface of a semiconductor substrate; depositing a first mask on the spacer; forming an aperture in the first mask; etching a recess in the surface of the substrate; depositing a first metal in the recess as a gate electrode and on the first mask; removing unneeded first metal by removing the first mask; burying the gate electrode by applying a second mask to the surface of the substrate and the spacer; etching the second mask to expose the gate electrode; depositing a second metal having a relatively high electrical conductivity on the gate electrode and second mask; applying a third mask having a larger thickness than that of the second mask on the second metal opposite the gate electrode; etching the second metal where it is not covered by the third mask and at the side walls of the layer of the second metal to produce a stripe of the second metal having a desired width; removing the third mask and the spacer except opposite the second mask; depositing a third metal to form ohmic electrodes at opposite sides of the gate electrode using the second mask for self-alignment of the ohmic electrodes; and annealing the gate electrode and the second metal to improve their adhesion.
Claim 3
Dependent Claim
21 words
A method of producing a semiconductor device as defined in claim 1 including depositing aluminum as the first and second metals.
Claim 4
Dependent Claim
25 words
A method of producing a semiconductor device as defined in claim 1 including depositing aluminum as the first metal and gold as the second metal.
Claim 5
Dependent Claim
23 words
A method of producing a semiconductor device as defined in claim 3 including depositing a barrier metal between the first and second metals.
Claim 6
Dependent Claim
22 words
A method of producing a semiconductor device as defined in claim 4 wherein said barrier metal comprises one of titanium and molybdenum.
Claim 7
Dependent Claim
22 words
A method of producing a semiconductor device as defined in claim 1 wherein the gate electrode is less than 0.5 micron wide.
Claim 8
Dependent Claim
20 words
A method of producing a semiconductor device as defined in claim 1 including depositing a glass material as the spacer.
Claim 9
Dependent Claim
25 words
A method of producing a semiconductor device as defined in claim 7 including stopping etching of the third mask when the glass material is reached.
Claim 10
Dependent Claim
26 words
A method of producing a semiconductor device as defined in claim 1 including depositing one of Si 3 N 4 and SiO 2 as the spacer.
Claim 11
Dependent Claim
36 words
A method of producing a semiconductor device as defined in claim 1 including anisotropically dry etching the second metal using the third mask and wet etching the side walls of the layer of the second metal.
Claim 12
Dependent Claim
35 words
A method of producing a semiconductor device as defined in claim 1 including etching the side walls of the second metal to produce a stripe of the second metal about 1 to 1.5 microns wide.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-07-15 | 1995-01-14 | 1995-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-15 | 1999-01-14 | 1999-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-15 | 2003-01-14 | 2003-07-16 | $7700.00 | Window Closed / Lapsed |