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Patent US4499651A successfully refreshed from Google Patents.
US4499651A
Expired / Lapsed
US
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Method of manufacturing a field-effect transistor
Assignee: Telefunken Electronic GmbH
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Filing: 1983-08-10
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Granted: 1985-02-19
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Expires: 2003-08-10
Abstract
Abstract In a method for the manufacture of a field-effect transistor comprising a substrate and an epitaxial layer located thereon, a V-shaped trench extending from the surface of the epitaxial layer through the epitaxial layer into the substrate is made and a zone is created by implantation in an area located in front of the V-shaped trench.
Inventors
- 👤 Erhard Kohn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:46
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/061; H10D30/0612; H10D64/00; H10D64/01; H10D64/012; H10D64/0124; H10D64/0125; H10D64/20; H10D64/27; H10D64/311; H10D64/411; H10P; H10P76/00; H10P76/40
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
59 words
A method of manufacturing a field-effect transistor comprising a substrate and an epitaxial layer thereon, wherein a V-shaped trench which extends from the surface of the epitaxial layer into the substrate is created, and a zone is formed by means of implantation in at least the area of the substrate located in front of and bordering the V-shaped trench.
Claim 2
Independent Claim
59 words
A method of manufacturing a field-effect transistor comprising a substrate and an epitaxial layer thereon, wherein a V-shaped trench which extends from the surface of the epitaxial layer into the substrate is created, and a zone is formed by means of implantation in at least the area of the substrate located in front of and bordering the V-shaped trench.
Claim 3
Dependent Claim
27 words
A method according to claim 1, wherein the substrate consists of a semi-insulating material or a semiconductor material of the opposite conductivity type than the epitaxial layer.
Claim 4
Dependent Claim
20 words
A method according to claim 1, wherein the implanted zone is of the same conductivity type as the epitaxial layer.
Claim 5
Dependent Claim
32 words
A method according to claim 1, wherein the V-shape of the trench and the thickness of the implanted zone are chosen so as to obtain a certain channel length in the substrate.
Claim 6
Dependent Claim
20 words
A method according to claim 1, wherein a passivation layer is produced on the epitaxial layer prior to the implantation.
Claim 7
Dependent Claim
20 words
A method according to claim 5, wherein the implanted zone is activated by annealing after the passivation layer is produced.
Claim 8
Dependent Claim
21 words
A method according to claim 6, wherein the annealing is carried out at a temperature in the range of 800° C.
Claim 9
Dependent Claim
21 words
A method according to claim 6, wherein the passivation layer is reinforced or subjected to passivation again prior to the annealing.
Claim 10
Dependent Claim
21 words
A method according to claim 6, wherein the passivation layer is removed following the annealing and activating of the implanted zone.
Claim 11
Dependent Claim
42 words
A method according to claim 9, wherein after the removal of the passivation layer, a second passivation layer is formed which covers the wall of the V-shaped trench with the exception of the portion of the trench wall located in the substrate.
Claim 12
Dependent Claim
21 words
A method according to claim 10, wherein the second passivation layer is an oxide layer formed by oxidation in an electrolyte.
Claim 13
Dependent Claim
15 words
A method according to claim 11, wherein the oxidation is carried out in the dark.
Claim 14
Dependent Claim
34 words
A method according to claim 11, wherein the voltage applied during oxidation is selected so as to be higher than the break-down voltage of the diode formed by the epitaxial layer and the electrolyte.
Claim 15
Dependent Claim
26 words
A method according to claim 11, wherein the voltage applied during oxidation is so selected that an oxide layer is formed only on the epitaxial layer.
Claim 16
Dependent Claim
22 words
A method according to claim 10, wherein a metal for a gate electrode is applied after formation of the second passivation layer.
Claim 17
Dependent Claim
20 words
A method according to claim 15, wherein TiAu, MoAu or TaMo is used as the metal for the gate electrode.
Claim 18
Dependent Claim
12 words
A method according to claim 15, wherein the gate electrode is vapor-deposited.
Claim 19
Dependent Claim
60 words
A method according to claim 17, wherein the metal for the gate electrode is vapor-deposited over the entire surface of the second passivation layer and of the portion of the trench wall in the substrate, and the section of the vapor-deposited metal layer which is not intended for the gate electrode is removed together with the oxide layer underneath it.
Claim 20
Independent Claim
151 words
A method of manufacturing a field effect transistor comprising: providing a substrate having an epitaxial layer of one conductivity type on one surface of the substrate and with the substrate consisting of a semi-insulating material or a semiconductor material of the opposite conductivity type than that of the epitaxial layer; creating a V-shaped trench which extends from the surface of the epitaxial layer into the substrate, and divides the epitaxial layer into two separate portions; by means of implantation, forming a zone of the same conductivity type as the epitaxial layer in at least the area of the substrate bordering the trench so as to provide a channel region for the transistor; applying a gate electrode to the surface of the portion of the trench in the substrate so as to contact the zone formed therein; and applying respective source and drain electrodes to the separate portions of the epitaxial layer.
Claim 21
Independent Claim
151 words
A method of manufacturing a field effect transistor comprising: providing a substrate having an epitaxial layer of one conductivity type on one surface of the substrate and with the substrate consisting of a semi-insulating material or a semiconductor material of the opposite conductivity type than that of the epitaxial layer; creating a V-shaped trench which extends from the surface of the epitaxial layer into the substrate, and divides the epitaxial layer into two separate portions; by means of implantation, forming a zone of the same conductivity type as the epitaxial layer in at least the area of the substrate bordering the trench so as to provide a channel region for the transistor; applying a gate electrode to the surface of the portion of the trench in the substrate so as to contact the zone formed therein; and applying respective source and drain electrodes to the separate portions of the epitaxial layer.
Claim 22
Dependent Claim
74 words
The method defined in claim 19 wherein said step of applying a gate electrode includes: forming an oxide layer which covers the walls of the trench other than the portion of the trench walls in the substrate by anodic oxidation in an electrolyte; depositing a metal over the entire surface of the walls of the trench including the portion having the oxide layer thereon; and removing the oxide layer and the overlying deposited metal.
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) | 1988-02-19 | 1988-08-20 | 1989-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-19 | 1992-08-20 | 1993-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-19 | 1996-08-20 | 1997-02-19 | $7700.00 | Window Closed / Lapsed |