US3981073A
Expired / Lapsed
US
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Lateral semiconductive device and method of making same
Assignee: Northrop Grumman Guidance and Electronics Co Inc
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Filing: 1974-07-26
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Granted: 1976-09-21
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Expires: 1994-07-26
Abstract
Abstract A lateral semiconductive device, such as a Gunn device or Impatt diode, is fabricated by depositing a barrier layer of beryllia over an epitaxial grown layer of N- type semiconductive material on an N+ type semiconductive wafer. The wafer is then thinned down, as by grinding and polishing. Electrode material is then deposited overlaying the N+ wafer layer for making ohmic contact thereto. The electrode material is etched to define at least a pair of laterally spaced electrodes, each making electrical connection to the epitaxial N- layer via the intervening layer of N+ wafer material. In the case of a Gunn device, the insulative barrier layer provides electrical insulation and prevents undesired leakage of current. In addition, it serves as a barrier to prevent metallic contact materials from diffusing into the epitaxial N- layer. Further, it serves as a heat sink between the active device and its mount. The electrode contacts are improved by their ohmic contact to the N+ wafer material on which the epitaxial N- active layer is grown.
Inventors
- 👤 Joseph H. Dully
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:37
CPC Classifications
H; H10; H10N; H10N80/00; H10N80/10; H10N80/107; H10D; H10D64/00; H10D64/01; H10D64/011; H10D8/00; H10D8/40; H10P; H10P14/00; H10P14/40; H10W; H10W40/00; H10W40/20; H10W40/25; H10W40/259; H10W72/00; H10W72/30; H10W72/071; H10W72/073; H10W72/07331; H10W72/07337; Y; Y10; Y10S; Y10S148/00; Y10S148/02; Y10S438/00; Y10S438/90; Y10S438/977
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
151 words
In a method for fabricating a lateral type semiconductive device the steps of: on an N+ type semiconductive wafer of sufficient thickness to be self-supporting, growing a thin N- type epitaxial layer of semiconductive material having a substantially lower N- type carrier concentration than said wafer, depositing a barrier layer of electrically insulative material on said epitaxial material, removing a layer of the wafer material from the side opposite said barrier layer, leaving a substantially thinned wafer, the composite of said thinned wafer, said epitaxial layer and said barrier layer being of sufficient thickness to be self-supporting depositing a layer of electrode material overlaying said wafer layer for making ohmic contact thereto; and selectively removing areas of said layers of said electrode material and wafer material to define a pair of laterally spaced electrodes each making electrical connection to said epitaxially grown layer via an intervening layer of said wafer material.
Claim 2
Dependent Claim
151 words
In a method for fabricating a lateral type semiconductive device the steps of: on an N+ type semiconductive wafer of sufficient thickness to be self-supporting, growing a thin N- type epitaxial layer of semiconductive material having a substantially lower N- type carrier concentration than said wafer, depositing a barrier layer of electrically insulative material on said epitaxial material, removing a layer of the wafer material from the side opposite said barrier layer, leaving a substantially thinned wafer, the composite of said thinned wafer, said epitaxial layer and said barrier layer being of sufficient thickness to be self-supporting depositing a layer of electrode material overlaying said wafer layer for making ohmic contact thereto; and selectively removing areas of said layers of said electrode material and wafer material to define a pair of laterally spaced electrodes each making electrical connection to said epitaxially grown layer via an intervening layer of said wafer material.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein said wafer and epitaxial materials are selected from the class consisting of gallium arsenide and indium phosphide.
Claim 4
Dependent Claim
13 words
The method of claim 1 wherein said barrier layer is made of beryllia.
Claim 5
Dependent Claim
32 words
The method of claim 1 wherein said layer of electrode material comprises a layer of gold making electrical contact to said underlaying wafer material via an intervening layer of gold and germanium.
Claim 6
Dependent Claim
16 words
The method of claim 1 wherein said epitaxial layer is of insufficient thickness to be self-supporting.
Claim 7
Dependent Claim
16 words
The method of claim 1 wherein said epitaxial layer is between 0.20 and 50 microns thick.
Claim 8
Dependent Claim
15 words
The method of claim 1 wherein said thinned wafer is thinner than said epitaxial layer.
Claim 9
Dependent Claim
21 words
The method of claim 1 including the step of depositing a layer of metal overlaying and interfacing with said barrier layer.
Claim 10
Dependent Claim
10 words
The method of claim 8 wherein said metal comprises gold.
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) | 1979-09-21 | 1980-03-22 | 1980-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-21 | 1984-03-22 | 1984-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-21 | 1988-03-22 | 1988-09-21 | $7700.00 | Window Closed / Lapsed |