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US5425860A
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Pulsed energy synthesis and doping of silicon carbide
Assignee: University of California
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Filing: 1993-04-07
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Granted: 1995-06-20
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Expires: 2013-04-07
Abstract
Abstract A method for producing beta silicon carbide thin films by co-depositing thin films of amorphous silicon and carbon onto a substrate, whereafter the films are irradiated by exposure to a pulsed energy source (e.g. excimer laser) to cause formation of the beta-SiC compound. Doped beta-SiC may be produced by introducing dopant gases during irradiation. Single layers up to a thickness of 0.5-1 micron have been produced, with thicker layers being produced by multiple processing steps. Since the electron transport properties of beta silicon carbide over a wide temperature range of 27°-730° C. is better than these properties of alpha silicon carbide, they have wide application, such as in high temperature semiconductors, including hetero-junction bipolar transistors and power devices, as well as in high bandgap solar arrays, ultra-hard coatings, light emitting diodes, sensors, etc.
Inventors
- 👤 Joel B. Truher
- 👤 James L. Kaschmitter
- 👤 Jesse B. Thompson
- 👤 Thomas W. Sigmon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:49
CPC Classifications
C; C23; C23C; C23C14/00; C23C14/58; C23C14/5806; C23C14/5813; C23C14/06; C23C14/0635; C23C14/5846
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
44 words
A method for producing beta silicon carbide thin films, comprising the steps of: co-depositing amorphous silicon and carbon on a substrate to form a thin film thereon; and irradiating the thus formed film with a pulsed energy source causing formation of beta silicon carbide.
Claim 2
Independent Claim
44 words
A method for producing beta silicon carbide thin films, comprising the steps of: co-depositing amorphous silicon and carbon on a substrate to form a thin film thereon; and irradiating the thus formed film with a pulsed energy source causing formation of beta silicon carbide.
Claim 3
Dependent Claim
21 words
The method of claim 1, wherein the step of co-depositing the silicon and carbon is carried out using a sputtering technique.
Claim 4
Dependent Claim
19 words
The method of claim 1, wherein the step of irradiating the film is carried out using an excimer laser.
Claim 5
Dependent Claim
24 words
The method of claim 1, wherein the step of irradiating the film is carried out using pulses of 308 nm XeCl excimer laser radiation.
Claim 6
Dependent Claim
18 words
The method of claim 4, wherein the pulses from the laser are 30 nanosecond (full-width at half-maximum) pulses.
Claim 7
Dependent Claim
35 words
The method of claim 1, additionally including the step of forming the substrate from the group consisting of silicon, fused silica, SiC, and plastics selected from the group of E-CTFE, E-TFE, PES, PVDF, and PTFE.
Claim 8
Dependent Claim
19 words
The method of claim 1, wherein the film is formed to a thickness not greater than about 1 micron.
Claim 9
Dependent Claim
21 words
The method of claim 7, additionally including the step of co-depositing multiple layers of amorphous silicon and carbon on the substrate.
Claim 10
Dependent Claim
29 words
The method of claim 1, additionally including the step of introducing at least one dopant gas during the step of irradiating the film for producing doped beta silicon carbide.
Claim 11
Dependent Claim
52 words
The method of claim 9, wherein the step of introducing the dopant gas is carried out by selecting at least one dopant gas from the group consisting of BF 3 , PF 5 , AsF 5 , and GaF 3 , and introducing the selected dopant into the processing chamber during irradiation.
Claim 12
Dependent Claim
15 words
The method of claim 1, wherein the silicon and carbon were co-deposited at room temperature.
Claim 13
Dependent Claim
26 words
The method of claim 11, wherein the step of co-depositing the silicon and carbon was carried out using argon in a DC magnetron sputtering deposition apparatus.
Claim 14
Dependent Claim
70 words
A process for selective synthesis of polycrystalline beta silicon carbide (3C polytype) from sputtered amorphous silicon carbide thin films using excimer laser radiation, comprising the step of: simultaneously depositing by sputtering a film of amorphous silicon and carbon on a fused silica substrate; and directing pulses of 308 nm XeCl excimer laser radiation onto the thus formed film to selectively crystallize areas in the film, thereby producing beta silicon carbide.
Claim 15
Dependent Claim
70 words
A process for selective synthesis of polycrystalline beta silicon carbide (3C polytype) from sputtered amorphous silicon carbide thin films using excimer laser radiation, comprising the step of: simultaneously depositing by sputtering a film of amorphous silicon and carbon on a fused silica substrate; and directing pulses of 308 nm XeCl excimer laser radiation onto the thus formed film to selectively crystallize areas in the film, thereby producing beta silicon carbide.
Claim 16
Dependent Claim
27 words
The process of claim 13, wherein the step of depositing by sputtering was carried out at room temperature using argon in a DC magnetron sputtering deposition apparatus.
Claim 17
Dependent Claim
27 words
The process of claim 13, wherein the step of directing pulses of laser radiation onto the film was carried out using 30 nanosecond (full-width at half-maximum) pulses.
Claim 18
Dependent Claim
29 words
The process of claim 15, additionally including the step of introducing a dopant into the processing chamber during laser irradiation of the film, thereby producing doped beta silicon carbide.
Claim 19
Dependent Claim
33 words
The process of claim 16, wherein the dopant is composed of at least one gas selected from the group consisting of BF 3 , PF 5 , AsF 5 and GaF 3 .
Claim 20
Dependent Claim
25 words
The process of claim 13, wherein the film of amorphous silicon and carbon was sputtered to a thickness of not greater than about one micron.
Claim 21
Dependent Claim
39 words
The method of claim 1, additionally including the steps of introducing at least one dopant gas after crystallization of the thus formed film by irradiation, and then irradiating with the pulsed energy source for producing doped beta silicon carbide.
Claim 22
Dependent Claim
20 words
The process of claim 16, wherein the step of introducing the dopant is carried out following crystallization by laser irradiation.
Claim 23
Dependent Claim
33 words
The method of claim 1, wherein the step of irradiating is carried out so that the temperature of the substrate does not exceed about 180° C. during irradiation of the thus formed film.
Claim 24
Dependent Claim
30 words
The process of claim 13, wherein the laser radiation is directed onto the thus formed film such that the temperature of the fused silica substrate does not exceed 180° C.
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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) | 1998-06-19 | 1998-12-19 | 1999-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-06-19 | 2002-12-19 | 2003-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-06-19 | 2006-12-19 | 2007-06-20 | $7700.00 | Window Closed / Lapsed |