US4545109A
Expired / Lapsed
US
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Method of making a gallium arsenide field effect transistor
Assignee: Fairchild Semiconductor Corp
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Filing: 1983-01-21
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Granted: 1985-10-08
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Expires: 2003-01-21
Abstract
Abstract A method of producing a high frequency III-V FET and the resultant structure is described wherein a doped layer is formed on a wafer of undoped, semi-insulating III-V material. The structure is then etched to form a mesa after which, a channel region is regrown from an exposed portion of the III-V substrate. The formation of the channel region defines the source and drain regions. Ohmic contacts are then made to the source and drain regions after which a Schottky contact is made to the channel region.
Inventors
- 👤 Walter F. Reichert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:51
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/17; H10D62/213; H10D62/221; H10D30/00; H10D30/80; H10D30/87; Y; Y10; Y10S; Y10S148/00; Y10S148/026; Y10S148/05; Y10S148/088; Y10S148/139
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
155 words
A method of producing a semiconductor device, comprising the steps of: forming a doped layer of a III-V compound material on the surface of a substrate of semi-insulating III-V compound material, the layer doped to a first concentration of a given conductivity type; forming a mesa by etching through portions of the doped layer and partially through the thickness of the substrate; forming a first aperture in the doped layer to expose a portion of the substrate; growing a channel region of the III-V compound material in the aperture to a sufficient thickness to extend laterally, partially over and insulated from the surface of the doped layer, the channel region doped to a second, lower concentration of the given conductivity type; forming a Schottky contact to the channel region; and forming ohmic contacts on the surface of the doped layer which are positioned such that the ohmic contacts are spaced apart from the channel region.
Claim 2
Independent Claim
155 words
A method of producing a semiconductor device, comprising the steps of: forming a doped layer of a III-V compound material on the surface of a substrate of semi-insulating III-V compound material, the layer doped to a first concentration of a given conductivity type; forming a mesa by etching through portions of the doped layer and partially through the thickness of the substrate; forming a first aperture in the doped layer to expose a portion of the substrate; growing a channel region of the III-V compound material in the aperture to a sufficient thickness to extend laterally, partially over and insulated from the surface of the doped layer, the channel region doped to a second, lower concentration of the given conductivity type; forming a Schottky contact to the channel region; and forming ohmic contacts on the surface of the doped layer which are positioned such that the ohmic contacts are spaced apart from the channel region.
Claim 3
Dependent Claim
50 words
The method of claim 1 comprising the further step of depositing a layer of insulating material on the doped layer; etching through the insulating material and the doped layer; and forming second apertures in the layer of insulating material to expose portions of the doped surface for ohmic contact thereto.
Claim 4
Dependent Claim
41 words
The method of claim 1 wherein the step of forming a mesa comprises: applying a layer of photoresist to areas of the doped layer; etching through the exposed doped layer, and portions of the substrate; and removing the layer of photoresist.
Claim 5
Dependent Claim
20 words
The method of claim 3, wherein: the doped layer is doped with silicon to a depth of about 0.2-0.5 microns.
Claim 6
Dependent Claim
39 words
The method of claim 4, wherein: the first concentration of dopant is of the order of about 10 18 /cm 3 ; and the second concentration of dopant is of the order of about 10 17 /cm 3 .
Claim 7
Dependent Claim
35 words
The method of claim 5, comprising the further step of: growing the channel region in the first aperture to a sufficient thickness to extend laterally, partially over the surface of the layer of insulating material.
Claim 8
Dependent Claim
23 words
The method of claim 6, wherein: the Schottky contact is formed by depositing successive layers of a AuGe/Ni/Au alloy on the channel region.
Claim 9
Dependent Claim
13 words
The method of claim 7, wherein: the III-V compound material is gallium arsenide.
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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) | 1988-10-07 | 1989-04-08 | 1989-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-07 | 1993-04-08 | 1993-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-07 | 1997-04-08 | 1997-10-08 | $7700.00 | Window Closed / Lapsed |