US4994413A
Expired / Lapsed
US
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Method of manufacturing a semiconductor device having a silicon carbide layer
Assignee: Fujitsu Semiconductor Ltd
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Filing: 1989-10-12
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Granted: 1991-02-19
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Expires: 2009-10-12
Abstract
Abstract A method of forming a semiconductor device on a silicon carbide layer comprises steps of introducing an impurity into selected parts of the silicon carbide layer, and oxidizing the silicon carbide layer by annealing in an atmosphere containing oxygen.
Inventors
- 👤 Takashi Eshita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:24
CPC Classifications
H; H10; H10D; H10D12/00; H10D12/01; H10D12/031; H10D62/00; H10D62/80; H10D62/83; H10D62/832; H10D62/8325; H10D84/00; H10D84/01; H10D84/02; H10D84/03; H10D84/035; H10W; H10W10/00; H10W10/01; Y; Y10; Y10S; Y10S148/00; Y10S148/048; Y10S257/00; Y10S257/906; Y10S438/00; Y10S438/931
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
165 words
A method of forming a semiconductor device on a silicon carbide layer, comprising the steps of: defining at least one device region and associated device isolation regions in the silicon carbide layer; selectively introducing an impurity into the device isolation regions of the silicon carbide layer at a concentration level sufficient to impart an enhanced rate of oxidation characteristic to said defined, device isolation regions, relatively to the rate of oxidation characteristic of the remainder of the silicon carbide layer including each said associated device region; oxidizing the silicon carbide layer by annealing in an oxidizing atmosphere and thereby forming an oxide layer on the silicon carbide layer, the oxide layer so formed in the device isolation regions being substantially thicker than that in each said associated device region and extending to a sufficient depth in the silicon carbide layer thereby to afford electrical isolation of a device to be formed in the associated device region; and forming a semiconductor device in the device region.
Claim 2
Independent Claim
165 words
A method of forming a semiconductor device on a silicon carbide layer, comprising the steps of: defining at least one device region and associated device isolation regions in the silicon carbide layer; selectively introducing an impurity into the device isolation regions of the silicon carbide layer at a concentration level sufficient to impart an enhanced rate of oxidation characteristic to said defined, device isolation regions, relatively to the rate of oxidation characteristic of the remainder of the silicon carbide layer including each said associated device region; oxidizing the silicon carbide layer by annealing in an oxidizing atmosphere and thereby forming an oxide layer on the silicon carbide layer, the oxide layer so formed in the device isolation regions being substantially thicker than that in each said associated device region and extending to a sufficient depth in the silicon carbide layer thereby to afford electrical isolation of a device to be formed in the associated device region; and forming a semiconductor device in the device region.
Claim 3
Dependent Claim
23 words
A method as claimed in claim 1 in which said impurity is selected from a group of elements comprising boron, phosphorus, and arsenic.
Claim 4
Dependent Claim
25 words
A method as claimed in claim 1 in which said impurity is introduced with a concentration level of about 1×10 19 cm -3 or more.
Claim 5
Dependent Claim
21 words
A method as claimed in claim 1 in which said impurity is introduced into the silicon carbide layer by ion implantation.
Claim 6
Dependent Claim
26 words
A method as claimed in claim 4 in which said ion implantation is made with a dose of about 10 14 -10 15 cm -2 .
Claim 7
Dependent Claim
20 words
A method as claimed in claim 1 which said annealing is performed at a temperature ranging from 950° C-1150° C.
Claim 8
Dependent Claim
20 words
A method as claimed in claim 1 in which said silicon carbide layer is formed on a single crystal silicon.
Claim 9
Dependent Claim
21 words
A method as claimed in claim 1 in which said silicon carbide layer is formed on a silicon carbide bulk crystal.
Claim 10
Dependent Claim
23 words
A method as claimed in claim 1 in which said silicon carbide layer is formed on a silicon layer grown on an insulator.
Claim 11
Dependent Claim
49 words
A method as claimed in claim 1 wherein said step of forming the semiconductor device comprises: providing a gate electrode on a part of the oxide layer covering said device region; and introducing an impurity into said device region by ion implantation using the gate electrode as a mask.
Claim 12
Dependent Claim
114 words
A method as claimed in claim 1 wherein said step of forming the semiconductor device comprises: exposing the silicon carbide layer at a part of the device region by removing the oxide layer therefrom; depositing a second silicon carbide layer with a conduction type opposite to the conduction type of the first silicon carbide layer so as to make a direct contact with the exposed part of the first silicon carbide layer; and depositing a third silicon carbide layer with a conduction type identical to that of the first silicon carbide layer so as to make a direct contact of said third silicon carbide layer with a part of the second silicon carbide layer.
Claim 13
Dependent Claim
48 words
A method as claimed in claim 1, wherein the silicon carbide layer is supported on a substrate, further comprising: performing said oxidizing step for a sufficient time to produce an oxide layer on each device isolation region which extends fully through the silicon carbide layer to the substrate.
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) | 1994-02-18 | 1994-08-20 | 1995-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-18 | 1998-08-20 | 1999-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-18 | 2002-08-20 | 2003-02-19 | $7700.00 | Window Closed / Lapsed |