EP0484096A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method of making recessed T-shaped Schottky gate field effect transistor
Assignee: Mitsubishi Electric Corp
•
Filing: 1991-10-29
•
Granted: —
•
Expires: 2011-10-29
Abstract
Abstract A method for fabricating a semiconductor device having a T-shaped gate electrode on a two-stepped recess includes the steps of forming an active layer in a substrate surface, forming two ohmic electrodes on the active layer, forming first side wall films on both side walls of the two ohmic electrodes, forming an upper stepped recess by etching the active layer using the first side wall films as a mask, forming second side wall films in the upper stepped recess to be in contact with the first side wall films, forming a lower stepped recess by etching the active layer exposed to the surface of the upper stepped recess using the second side wall films as a mask, and forming a T-shaped gate in the lower stepped recess with its shoulder parts on the second side wall films.
Inventors
- 👤 Mitsunori c/o Mitsubishi Denki K.K. Nakatani
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 05:25
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/061; H10D30/0612; H10D30/80; H10D30/87; H10D30/877; H10D64/00; H10D64/01; H10D64/012; H10D64/0124; H10D64/0125; H10D64/0126; H10D64/20; H10D64/27; H10D64/311; H10D64/411
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
143 words
A method for fabricating a semiconductor device having a T-shaped gate electrode in a two-stepped recess comprising the steps of: forming an active layer in a substrate surface; forming two ohmic electrodes having different thicknesses from each other on said active layer; forming first side wall films on both side walls of said two ohmic electrodes; forming an upper stepped recess by etching said active layer using said first side wall films as a mask; forming second side wall films in said upper stepped recess to be in contact with said first side wall films; forming a lower stepped recess by etching said active layer exposed to the surface of said upper stepped recess using said second side wall films as a mask; and forming a T-shaped gate in said lower stepped recess with its shoulder parts on said second side wall films.
Claim 2
Dependent Claim
19 words
A method for fabricating a semiconductor device in accordance with claim 1 wherein said substrate is a semi-insulating substrate.
Claim 3
Dependent Claim
17 words
A method for fabricating a semiconductor device in accordance with claim 2 wherein said substrate is GaAs.
Claim 4
Dependent Claim
73 words
A method for fabricating a semiconductor device in accordance with claim 1 which further comprises, after the formation of said T-shaped gate, removing said first side wall film and said second side wall film on one of said ohmic electrodes and forming metal at least on said one ohmic electrode and on the active layer where said first and second side wall films are removed, to be in ohmic contact with these layers.
Claim 5
Dependent Claim
21 words
A method for fabricating a semiconductor device in accordance with claim 4 wherein said one ohmic electrode is a source electrode.
Claim 6
Independent Claim
115 words
A method for fabricating a semiconductor device having a T-shaped gate electrode in a two-stepped recess comprising the steps of: forming an active layer in a substrate surface; forming two ohmic electrodes on said active layer; forming an upper stepped recess by etching said active layer using said two ohmic electrodes as a mask; forming side wall films on the side wall of said ohmic electrodes and in said upper stepped recess; forming a lower stepped recess by etching said active layer exposed to said upper stepped recess using said side wall films as a mask; and forming a T-shaped gate on said lower stepped recess with its shoulder parts on said side wall films.
Claim 7
Dependent Claim
19 words
A method for fabricating a semiconductor device in accordance with claim 6 wherein said substrate is a semi-insulating substrate.
Claim 8
Dependent Claim
17 words
A method for fabricating a semiconductor device in accordance with claim 6 wherein said substrate is GaAs.
Claim 9
Independent Claim
85 words
A method for fabricating a semiconductor device having a T-shaped gate electrode in a one-stepped recess comprising the steps of: forming an active layer in a substrate surface; forming two ohmic electrodes on said active layer; forming a recess by etching said active layer using said two ohmic electrodes as a mask; forming side wall films on the side walls of said ohmic electrodes and in said recess; and forming a T-shaped gate in said recess with its shoulder parts on said side wall films.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.