US4671847A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermally-activated vapor etchant for InP
Assignee: United States Department of the Navy
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Filing: 1985-11-18
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Granted: 1987-06-09
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Expires: 2005-11-18
Abstract
Abstract Vapor from liquid ethylene dibromide (EDB) functions in a manner superior anhydrous HCl for in situ gas phase etching of InP substrates in Metalorganic Vapor Phased Epitaxy (MOVPE). The etch rate and surface morphology behaviors have been determined for conditions useful as a substrate cleaning step prior to growth of InP and InGaAs epilayers. The thermally activated decomposition and etching are analogous to group III-V semiconductor growth processes; the behavior in different carrier gas mixtures demonstrates dependence on gas phase reactions in the heated vapor above the substrate.
Inventors
- 👤 Arthur R. Clawson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:36
CPC Classifications
H; H10; H10P; H10P90/00; H10P90/12; H10P90/126; H10P50/00; H10P50/20; H10P50/24; H10P50/246; Y; Y10; Y10S; Y10S148/00; Y10S148/119
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
42 words
A method for etching an InP substrate to assure the removal of surface contaminants, oxides and mechanical damage comprising: heating the InP substrate; vaporizing ethylene dibromide; and flowing the vaporized ethylene dibromide over the heated InP substrate to assure the etching thereof.
Claim 2
Independent Claim
42 words
A method for etching an InP substrate to assure the removal of surface contaminants, oxides and mechanical damage comprising: heating the InP substrate; vaporizing ethylene dibromide; and flowing the vaporized ethylene dibromide over the heated InP substrate to assure the etching thereof.
Claim 3
Dependent Claim
35 words
A method according to claim 1 further including: mounting the InP substrate on a graphite susceptor having a thermocouple that is coupled to an RF induction heater to assure the heating of the InP substrate.
Claim 4
Dependent Claim
42 words
A method according to claim 2 in which the step of heating includes: heating of a graphite susceptor and mounted InP substrate by an RF induction heater connected to a thermocouple in the susceptor to a temperature in excess of 650° C.
Claim 5
Dependent Claim
19 words
A method according to claim 3 in which the step of heating is to a temperature of 675° C.
Claim 6
Dependent Claim
30 words
A method according to claim 4 in which the etching of the InP substrate depends on gas-phase reactions in heated vapor above the InP substrate during the step of flowing.
Claim 7
Dependent Claim
29 words
A method according to claim 5 in which the step of flowing includes the mixing of the ethylene dibromide with a mixed H 2 and N 2 carrier gas.
Claim 8
Dependent Claim
21 words
A method according to claim 6 further including: introducing a PH 3 concentration into flowing ethylene dibromide to prevent surface degradation.
Claim 9
Dependent Claim
37 words
A method according to claim 7 in which the ethylene dibromide has a concentration of about 1.3×10 -4 atm. at a total gas flow of 2 SLM with a PH 3 concentration of about 5.5×10 -3 atm.
Claim 10
Dependent Claim
21 words
A method according to claim 5 further including: introducing a PH 3 concentration into flowing ethylene dibromide to prevent surface degradation.
Claim 11
Dependent Claim
15 words
A method according to claim 5 in which an H 2 carrier gas is provided.
Claim 12
Dependent Claim
21 words
A method according to claim 5 in which a carrier gas of 25% H 2 and 75% N 2 is provided.
Claim 13
Dependent Claim
21 words
A method according to claim 5 in which a carrier gas of 75% H 2 and 25% N 2 is provided.
Claim 14
Dependent Claim
25 words
A method according to claim 5 in which a carrier gas of N 2 is provided with He added to influence the rate of etching.
Claim 15
Dependent Claim
22 words
A method according to claim 1 in which the rate of etching is dependent of the rate of the step of flowing.
Claim 16
Dependent Claim
20 words
A method according to claim 1 further including: introducing phsophine into the flowing of ethylene dibromide to maintain smooth surfaces.
Claim 17
Dependent Claim
30 words
A method according to claim 1 in which the step of vaporizing includes the bubbling of H 2 gas through room temperature ethylene dibromide prior to the step of flowing.
Claim 18
Dependent Claim
30 words
A method according to claim 1 in which the step of vaporizing includes the bubbling of N 2 gas through room temperature ethylene dibromide prior to the step of flowing.
References Cited (Backward Citations)
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US3522118A
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US3855024A
Cited
JPS5120973A
Cited
US4349394A
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US4397711A
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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) | 1990-06-08 | 1990-12-08 | 1991-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-08 | 1994-12-08 | 1995-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-08 | 1998-12-08 | 1999-06-09 | $7700.00 | Window Closed / Lapsed |