EP0106174A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Manufacture of a Schottky FET
Assignee: Hitachi Ltd
•
Filing: 1983-09-15
•
Granted: —
•
Expires: 2003-09-15
Abstract
Abstract This specification discloses a self-aligned manufacturing method of a Schottky gate FET. This method comprises the steps: forming a gate metallic layer (3) on a semiconductor substrate (1) and a mask (10; 16, 17) overhanging the metallic layer (3); ion-implanting impurity ions into the semi-conductor substrate using the mask to form a source/ drain region (6, 7); depositing an insulator (19, 20) on the gate metallic layer side surface (21) and the other surface below the mask; directionally etching said deposited insulator (19, 20) using the mask to expose the source/drain region (6, 7); depositing a source/drain electrode (4, 5) using the mask; and removing the mask.
Inventors
- 👤 Kiichi Ueyanagi
- 👤 Yasunari Umemoto
- 👤 Susumu Takahashi
- 👤 Michiharu Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 19:54
CPC Classifications
H; H10; H10P; H10P30/00; H10P30/20; H10P30/21; H10D; H10D30/00; H10D30/01; H10D30/061; H10D30/0612; H10D30/0616; H10D30/60; H10D30/80; H10D30/87; H10P30/202; H10P30/206; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; Y; Y10; Y10S; Y10S148/00; Y10S148/083; Y10S148/143
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
191 words
1 . A method of manufacturing a Schottky gate FET comprising the steps of: (a) forming a gate electrode (3) of metallic material and a mask member (10; 16, 17) on a semi- conductor substrate (1), said gate electrode of metallic material being in Schottky contact to the semiconductor substrate, said-mask member overhanging a periphery of the gate electrode (3); (b) ion-implanting impurities into the semi- conductor substrate (1) using said mask member (10; 16, 17) as a mask, to form a source region (6) and a drain region (7) thereby forming an intermediate structure; (c) depositing insulator (19, 20) on a surface of the intermediate structure, including a side surface (21) of the gate electrode (3) overhung by the mask member (10; 16, 17); (d) etching said deposited insulator (19, 2.0) to expose the source region (6) and the drain region (7) using at least said mask member (10; 16, 17) as a mask, while leaving the insulator at least at the side surface (21) of the gate electrode; and (e) forming a source electrode (3) and a drain electrode (4) on the exposed source and drain regions (6, 7).
Claim 2
Dependent Claim
191 words
1 . A method of manufacturing a Schottky gate FET comprising the steps of: (a) forming a gate electrode (3) of metallic material and a mask member (10; 16, 17) on a semi- conductor substrate (1), said gate electrode of metallic material being in Schottky contact to the semiconductor substrate, said-mask member overhanging a periphery of the gate electrode (3); (b) ion-implanting impurities into the semi- conductor substrate (1) using said mask member (10; 16, 17) as a mask, to form a source region (6) and a drain region (7) thereby forming an intermediate structure; (c) depositing insulator (19, 20) on a surface of the intermediate structure, including a side surface (21) of the gate electrode (3) overhung by the mask member (10; 16, 17); (d) etching said deposited insulator (19, 2.0) to expose the source region (6) and the drain region (7) using at least said mask member (10; 16, 17) as a mask, while leaving the insulator at least at the side surface (21) of the gate electrode; and (e) forming a source electrode (3) and a drain electrode (4) on the exposed source and drain regions (6, 7).
Claim 3
Dependent Claim
26 words
A method of manufacturing a Schottky gate FET according to Claim 1 wherein said insulator depositing step (c) includes vapor-depositing nitride (20) at a reduced pressure.
Claim 4
Dependent Claim
36 words
A method of manufacturing a Schottky gate FET according to Claim 1 wherein said deposited insulator comprises an oxide underlie (19) deposited at atmospheric pressure and a nitride layer (20) deposited thereon at a reduced pressure.
Claim 5
Dependent Claim
24 words
A method of manufacturing a Schottky gate FET according to Claim 2 wherein said nitride depositing step comprises plasma chemical vapor deposition (CVD) .
Claim 6
Dependent Claim
20 words
A method of manufacturing a Schottky gate FET according to Claim 1 wherein said etching step (d) comprises directional etching.
Claim 7
Dependent Claim
20 words
A method of manufacturing a Schottky gate FET according to Claim 1 wherein said etching step (d) includes dry etching.
Claim 8
Dependent Claim
38 words
A method of manufacturing a Schottky gate FET according to Claim 2 wherein said etching step (d) includes dry etching using (CF 4 + 0 2 ) gas containing small amounts of N 2 and H 2 .
Claim 9
Dependent Claim
45 words
A method of manufacturing a Schottky gate FET according to Claim 3 wherein said etching step (d) includes dry etching using (CF 4 +O 2 ) gas containing small amounts of N 2 and H 2 and wet etching using etching liquid containing hydrofluoric acid.
Claim 10
Dependent Claim
70 words
A method of manufacturing a Schottky gate FET according to Claim 1 wherein said step (a) includes forming an oxide film (17) and a photoresist film (16) gate electrode of a metallic material (15), photoetching the oxide film (17) using the photoresist film (16) as a mask, and etching the gate electrode of the metallic material (15) using the photoresist film (16) and the oxide film (17) as a mask.
Claim 11
Dependent Claim
29 words
A method of manufacturing a Schottky gate FET according to Claim 9 wherein said etching of the gate electrode includes plasma etching using (CF 4 +O 2 ) gas.
Claim 12
Dependent Claim
34 words
A method of manufacturing a Schottky gate FET according to Claim 10 wherein said plasma etching provides a side-etch of about 0.1 - 0.4 µm from an edge of the mask member (16, 17).
Claim 13
Dependent Claim
39 words
A method of manufacturing a Schottky gate FET according to Claim 10 wherein said depositing step (c) includes depositing thin oxide film (19) on the semiconductor substrate surface and a nitride film (20) thicker than the oxide film thereon.
Claim 14
Dependent Claim
21 words
A method of manufacturing a Schottky gate FET according to Claim 12 wherein said depositing step (c) is effected by CVD.
Claim 15
Dependent Claim
31 words
A method of manufacturing a Schottky gate FET according to Claim 13 wherein said etching step (d) is dry etching using a gas containing CF 4 achieved under a reduced pressure.
Claim 16
Dependent Claim
45 words
A method of manufacturing a Schottky gate FET according to Claim 14 wherein said reduced pressure dry etching is effected in an atmosphere of a reduced pressure mixed (CF 4 + 0 2 ) gas containing small amounts of N 2 and H 2 .
Claim 17
Dependent Claim
35 words
A method of manufacturing a Schottky gate FE T according to Claim 14 wherein said gate metallic material (15) contains at least one of Ti/W, silicides and nitrides of Ti, W, Ti/W, Ta and Hf.
Claim 18
Independent Claim
146 words
A method of manufacturing a Schottky gate GaAs FET comprising the steps of: forming a Schottky gate electrode (3) on a GaAs substrate (1) and a mask member (10; 16, 17) overhanging the gate electrode (3), the gate electrode being formed of a material selected from the group consisting of Ti, W, alloy of Ti and W, Ta, Hf, silicides and nitrides thereof, the overhanging mask including a silicon oxide layer (17); depositing an insulator layer (19, 20) on the exposed surfaces of the substrate (1), the gate electrode (3) and the mask member (10; 16, 17), the insulator layer including a silicon nitride layer (20); directionally etching the insulator layer (19, 20) using said mask member (10; 16, 17) as an etching mask to expose part of the GaAs substrate (1); and depositing current electrode (4, 5) on the exposed part of the GaAs substrate.
Claim 19
Independent Claim
146 words
A method of manufacturing a Schottky gate GaAs FET comprising the steps of: forming a Schottky gate electrode (3) on a GaAs substrate (1) and a mask member (10; 16, 17) overhanging the gate electrode (3), the gate electrode being formed of a material selected from the group consisting of Ti, W, alloy of Ti and W, Ta, Hf, silicides and nitrides thereof, the overhanging mask including a silicon oxide layer (17); depositing an insulator layer (19, 20) on the exposed surfaces of the substrate (1), the gate electrode (3) and the mask member (10; 16, 17), the insulator layer including a silicon nitride layer (20); directionally etching the insulator layer (19, 20) using said mask member (10; 16, 17) as an etching mask to expose part of the GaAs substrate (1); and depositing current electrode (4, 5) on the exposed part of the GaAs substrate.
Claim 20
Dependent Claim
30 words
A method of manufacturing a Schottky gate GaAs FET according to Claim 17, wherein said step of forming a Schottky gate electrode includes isotropic dry etching utilizing a fluorine-containing gas.
Claim 21
Dependent Claim
40 words
A method of manufacturing a Schottky gate GaAs FET according to Claim 17, wherein said directional etching step includes an isotropic reactive dry etching utilizing a fluorine-containing gas having a higher etching rate for silicon nitride than for silicon oxide.
Claim 22
Independent Claim
173 words
A method of manufacturing a Schottky gate FET, comprising the steps of: forming a shallow doped region (2) in a surface of a semiconductor substrate (1); depositing a layer (15) of Schottky material on the surface of the semiconductor substrate to form a Schottky contact therewith; forming an insulator layer (10; 16, 17) on the surface of the layer (15) of Schottky material; patterning the insulator layer (10; 16, 17) to form a mask member; overly etching the layer (15) of Schottky material using said mask member (10; 16, 17) as an etching mask to form a Schottky gate electrode (3) and to indent the side surface of the Schottky gate electrode below the mask member (10; 16, 17); depositing another insulator layer (19, 20) at least on the side surface of the Schottky gate electrode (3); directionally etching said another insulator layer (19, 20) using said mask member (10; 16, 17) as an etching mask to expose the substrate surface; and depositing a metal layer (4, 5) on the exposed substrate surface.
Claim 23
Independent Claim
173 words
A method of manufacturing a Schottky gate FET, comprising the steps of: forming a shallow doped region (2) in a surface of a semiconductor substrate (1); depositing a layer (15) of Schottky material on the surface of the semiconductor substrate to form a Schottky contact therewith; forming an insulator layer (10; 16, 17) on the surface of the layer (15) of Schottky material; patterning the insulator layer (10; 16, 17) to form a mask member; overly etching the layer (15) of Schottky material using said mask member (10; 16, 17) as an etching mask to form a Schottky gate electrode (3) and to indent the side surface of the Schottky gate electrode below the mask member (10; 16, 17); depositing another insulator layer (19, 20) at least on the side surface of the Schottky gate electrode (3); directionally etching said another insulator layer (19, 20) using said mask member (10; 16, 17) as an etching mask to expose the substrate surface; and depositing a metal layer (4, 5) on the exposed substrate surface.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.