US6403982B2
Expired / Lapsed
US
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Semi-insulating silicon carbide without vanadium domination
Assignee: Wolfspeed Inc
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Filing: 2001-01-10
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Granted: 2002-06-11
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Expires: 2021-01-10
Abstract
Abstract A semi-insulating bulk single crystal of silicon carbide is disclosed that has a resistivity of at least 5000 OMEGA-cm at room temperature and a concentration of deep level trapping elements that is below the amounts that will affect the resistivity of the crystal, preferably below detectable levels. A method of forming the crystal is also disclosed, along with some resulting devices that take advantage of the microwave frequency capabilities of devices formed using substrates according to the invention.
Inventors
- 👤 Calvin H. Carter, Jr.
- 👤 Mark Brady
- 👤 Valeri F. Tsvetkov
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:56
CPC Classifications
C; C30; C30B; C30B23/00; C30B29/00; C30B29/10; C30B29/36; C30B33/00
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
51 words
A semi-insulating bulk single crystal of silicon carbide having a resistivity of at least 5000 Ω-cm at room temperature, a concentration of deep level trapping elements that is below the amount that affects the electrical characteristics of the crystal, and a concentration of nitrogen atoms below 1×10 17 cm −3 .
Claim 2
Dependent Claim
51 words
A semi-insulating bulk single crystal of silicon carbide having a resistivity of at least 5000 Ω-cm at room temperature, a concentration of deep level trapping elements that is below the amount that affects the electrical characteristics of the crystal, and a concentration of nitrogen atoms below 1×10 17 cm −3 .
Claim 3
Dependent Claim
30 words
A silicon carbide single crystal according to claim 1 wherein the polytype of the silicon carbide is selected from the group consisting of the 3C, 4H, 6H and 15R polytypes.
Claim 4
Dependent Claim
21 words
A silicon carbide single crystal according to claim 1 having a concentration of nitrogen atoms below 1×10 17 cm −3 .
Claim 5
Dependent Claim
21 words
A silicon carbide single crystal according to claim 1 wherein the concentration of nitrogen is 5×10 16 cm −3 or less.
Claim 6
Dependent Claim
31 words
A silicon carbide single crystal according to claim 1 wherein the concentration of deep level trapping elements is below the level that can be detected by secondary ion mass spectroscopy (SIMS).
Claim 7
Dependent Claim
27 words
A silicon-carbide single crystal according to claim 1 wherein the concentration of vanadium is below the level that can be detected by secondary ion mass spectroscopy (SIMS).
Claim 8
Dependent Claim
22 words
A silicon carbide single crystal according to claim 1 wherein the concentration of vanadium is less than 1×10 16 cm −3 .
Claim 9
Dependent Claim
22 words
A silicon carbide single crystal according to claim 1 wherein the concentration of vanadium is less than 1×10 14 cm −3 .
Claim 10
Dependent Claim
20 words
A silicon carbide single crystal according to claim 1 having a resistivity of at least 50,000 Ω-cm at room temperature.
Claim 11
Dependent Claim
16 words
A transistor having a substrate that comprises the bulk single crystal according to claim 1 .
Claim 12
Dependent Claim
24 words
A transistor according to claim 10 selected from the group consisting of: metal-semiconductor field-effect transistors, metal-insulator field effect transistors, and high electron mobility transistors.
Claim 13
Dependent Claim
42 words
A semi-insulating bulk single crystal of silicon carbide having a resistivity of at least 5000 Ω-cm at room temperature and a concentration of deep level trapping elements that is below the level that can be detected by secondary ion mass spectroscopy (SIMS).
Claim 14
Dependent Claim
42 words
A semi-insulating bulk single crystal of silicon carbide having a resistivity of at least 5000 Ω-cm at room temperature and a concentration of deep level trapping elements that is below the level that can be detected by secondary ion mass spectroscopy (SIMS).
Claim 15
Dependent Claim
33 words
A semi-insulating bulk single crystal of silicon carbide having a resistivity of at least 5000 Ω-cm at room temperature and a concentration of vanadium that is less than 1×10 16 cm −3 .
Claim 16
Dependent Claim
33 words
A semi-insulating bulk single crystal of silicon carbide having a resistivity of at least 5000 Ω-cm at room temperature and a concentration of vanadium that is less than 1×10 16 cm −3 .
Claim 17
Dependent Claim
40 words
A semi-insulating bulk single crystal of silicon carbide having a resistivity of at least 50000 Ω-cm at room temperature and a concentration of deep level trapping elements that is below the amount that affects the electrical characteristics of the crystal.
Claim 18
Dependent Claim
40 words
A semi-insulating bulk single crystal of silicon carbide having a resistivity of at least 50000 Ω-cm at room temperature and a concentration of deep level trapping elements that is below the amount that affects the electrical characteristics of the crystal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2005-06-10 | 2005-12-10 | 2006-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-06-10 | 2009-12-10 | 2010-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-06-10 | 2013-12-10 | 2014-06-11 | $7700.00 | Window Closed / Lapsed |