US5264382A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing semiconductor device using dummy gate structure
Assignee: Fujitsu Ltd
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Filing: 1991-03-18
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Granted: 1993-11-23
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Expires: 2011-03-18
Abstract
Abstract A method of producing a semiconductor device (MESFET) which includes the following steps (a) to (h): (a) forming a trapezium dummy gate, which is made of a first insulating material (SiO 2 ) and has two normal slopes, on a semiconductor substrate (of a compound semiconductor); (b) selectively forming ohmic electrodes, coming in contact with the dummy gate, on the semiconductor substrate; (c) forming an element isolation region in the semiconductor substrate; (d) forming an insulating film of a second insulating material (Si 3 N 4 ), different from the first insulating material, over the entire surface; (e) selectively removing projected portions of the dummy gate and insulating film to make a flat portion composed of the remaining dummy gate and insulating film; (f) removing the dummy gate to form an opening having two reverse slopes; (g) forming a sidewall portion of a third insulating material (SiO 2 ), which is different from the second insulating material, on the reverse slopes of the opening to form a gate opening corresponding to a narrower gate length; and (h) forming a gate electrode to thereby fill the gate opening.
Inventors
- 👤 Yuu Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:01
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/061; H10D30/0612; H10D30/0614; H10D30/80; H10D30/87; H10D64/00; H10D64/01; H10D64/012; H10D64/0124; H10D64/0125; H10D64/017; H10W; H10W20/00; H10W20/01; H10W20/071; H10W20/081
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
206 words
A method of producing a semiconductor device, which comprises the following steps: forming a trapezium dummy gate, which includes a first insulating material and which has two side slopes each having an oblique angle of less than 90°, on a semiconductor substrate; forming a metal layer for ohmic contact electrodes on said semiconductor substrate and on a mask layer which is formed on said dummy gate; removing said mask layer and a portion of said metal layer on said mask layer and selectively removing said metal layer to form said ohmic electrodes coming in contact with said dummy gate, on said semiconductor substrate; forming an insulating film of a second insulating material different from said first insulating material, over the entire surface; selectively removing projected portions of said dummy gate and insulating film to make a flat portion composed of the remaining dummy gate and insulating film; removing said dummy gate to form an opening having two side slopes each having a supplementary angle to a respective side slope of said trapezium dummy gate; forming a sidewall portion of a third insulating material on the side slopes of said opening to form a gate opening; and forming a gate electrode to therein fill said gate opening.
Claim 2
Independent Claim
206 words
A method of producing a semiconductor device, which comprises the following steps: forming a trapezium dummy gate, which includes a first insulating material and which has two side slopes each having an oblique angle of less than 90°, on a semiconductor substrate; forming a metal layer for ohmic contact electrodes on said semiconductor substrate and on a mask layer which is formed on said dummy gate; removing said mask layer and a portion of said metal layer on said mask layer and selectively removing said metal layer to form said ohmic electrodes coming in contact with said dummy gate, on said semiconductor substrate; forming an insulating film of a second insulating material different from said first insulating material, over the entire surface; selectively removing projected portions of said dummy gate and insulating film to make a flat portion composed of the remaining dummy gate and insulating film; removing said dummy gate to form an opening having two side slopes each having a supplementary angle to a respective side slope of said trapezium dummy gate; forming a sidewall portion of a third insulating material on the side slopes of said opening to form a gate opening; and forming a gate electrode to therein fill said gate opening.
Claim 3
Dependent Claim
16 words
A method according to claim 1, wherein said oblique angle is from 75 to 60 degrees.
Claim 4
Dependent Claim
26 words
A method according to claim 1, wherein said semiconductor substrate consists of a semi-insulating compound semiconductor substrate and a compound semiconductor active layer epitaxially grown thereon.
Claim 5
Dependent Claim
15 words
A method according to claim 1, wherein said semiconductor device is a metal-semiconductor field-effect transistor.
Claim 6
Dependent Claim
49 words
A method according to claim 1, wherein said sidewall portion formation step comprises a step of forming a film of said third insulating material on a whole surface including said opening, and then a step of anisotropically etching said third insulating material film, to leave said sidewall portion only.
Claim 7
Independent Claim
177 words
A method of producing a semiconductor device, which comprises the following steps: (a) forming a trapezium dummy gate, which includes a first insulating material and which has two side slopes each having an oblique angle of less than 90°, on a semiconductor substrate; (b) selectively forming ohmic electrodes coming in contact with said dummy gate, on said semiconductor substrate; (c) forming an element isolation region in said semiconductor substrate; (d) forming an insulating film of a second insulating material different from said first insulating material, over the entire surface; (e) selectively removing projected portions of said dummy gate and insulating film to make a flat portion composed of the remaining dummy gate and insulating film; (f) removing said dummy gate to form an opening having two side slopes each having a supplementary angle to a respective side slope of said trapezium dummy gate; (g) forming a sidewall portion of a third insulating material on the side slopes of said opening to form a gate opening; and (h) forming a gate electrode to therein fill said gate opening.
Claim 8
Independent Claim
177 words
A method of producing a semiconductor device, which comprises the following steps: (a) forming a trapezium dummy gate, which includes a first insulating material and which has two side slopes each having an oblique angle of less than 90°, on a semiconductor substrate; (b) selectively forming ohmic electrodes coming in contact with said dummy gate, on said semiconductor substrate; (c) forming an element isolation region in said semiconductor substrate; (d) forming an insulating film of a second insulating material different from said first insulating material, over the entire surface; (e) selectively removing projected portions of said dummy gate and insulating film to make a flat portion composed of the remaining dummy gate and insulating film; (f) removing said dummy gate to form an opening having two side slopes each having a supplementary angle to a respective side slope of said trapezium dummy gate; (g) forming a sidewall portion of a third insulating material on the side slopes of said opening to form a gate opening; and (h) forming a gate electrode to therein fill said gate opening.
Claim 9
Dependent Claim
17 words
A method according to claim 6, wherein said element isolation region is formed by an ion-implantation process.
Claim 10
Dependent Claim
28 words
A method according to claim 6, wherein said element isolation region is formed by selectively etching said semiconductor substrate not covered with said dummy gate and ohmic electrodes.
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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) | 1996-11-22 | 1997-05-24 | 1997-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-11-22 | 2001-05-24 | 2001-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-11-22 | 2005-05-24 | 2005-11-23 | $7700.00 | Window Closed / Lapsed |