US4033843A
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Simple method of preparing structurally high quality PbSnTe films
Assignee: Hughes Missile Systems Co
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Filing: 1976-05-27
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Granted: 1977-07-05
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Expires: 1996-05-27
Abstract
Abstract The method of the present invention comprises depositing by sputtering, from a single target or source, a thin high quality single crystal film in a predictable and repeatable manner having the general formula Pb 1 -x Sn x Te, where x may range from 0.00 to 0.30. The film has infrared sensing properties with a cutoff wavelength λ c from about 6μm to greater than 25μm. Structurally high quality film can be deposited on a large number of single crystal substrates of, for example CaF 2 (100 or 111) or BaF 2 (111), PbTe and PbSnTe, in a low pressure atmosphere by supported discharge sputtering or ion beam sputtering at substrate temperatures between about 220° and 350° C and at film growth rates from 0.1 to 3.0μm/hr. In the case of supported discharge sputtering the voltage to the target and/or the ion (plasma) current is varied to control the rate of film deposition. In the case of ion beam sputtering, the ion beam energy and/or ion beam current is varied to control the rate of film deposition.
Inventors
- 👤 Esther Krikorian
- 👤 Richard J. Sneed
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 19:44
CPC Classifications
C; C23; C23C; C23C14/00; C23C14/22; C23C14/34; C23C14/35
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
23 words
A method of predictably preparing high structural quality, single-crystal Pb 1 -x Sn x Te films having infrared sensing properties, said method comprising:
Claim 2
Independent Claim
23 words
A method of predictably preparing high structural quality, single-crystal Pb 1 -x Sn x Te films having infrared sensing properties, said method comprising:
Claim 3
Dependent Claim
130 words
sputtering from a single Pb 1 -x Sn x Te target a single crystal Pb 1 -x Sn x Te film on a selected single crystal substrate in a selected inert gas atmosphere in a reaction zone at pressures below 10 μm after first having evacuated said reaction zone to at least about 10 - 7 torr, said sputtering employing control of substrate temperature and film growth rate where substrate temperature is selected from a range from about 220° to about 350° C. and the film growth rate is selected from a range from about 0.1 to about 3.0 μm/hr., with the higher of said growth rates typically used with the higher of said temperatures and the lower of said growth rates typically used with the lower of said temperatures.
Claim 4
Dependent Claim
130 words
sputtering from a single Pb 1 -x Sn x Te target a single crystal Pb 1 -x Sn x Te film on a selected single crystal substrate in a selected inert gas atmosphere in a reaction zone at pressures below 10 μm after first having evacuated said reaction zone to at least about 10 - 7 torr, said sputtering employing control of substrate temperature and film growth rate where substrate temperature is selected from a range from about 220° to about 350° C. and the film growth rate is selected from a range from about 0.1 to about 3.0 μm/hr., with the higher of said growth rates typically used with the higher of said temperatures and the lower of said growth rates typically used with the lower of said temperatures.
Claim 5
Dependent Claim
15 words
The method of claim 1 wherein said selected inert gas atmosphere consists essentially of argon.
Claim 6
Dependent Claim
26 words
The method of claim 1 wherein said film has the formula Pb 1 -x Sn x Te where x can range from 0.0 to about 0.3.
Claim 7
Dependent Claim
25 words
The method of claim 3 wherein said sputtering target is Pb 1 -x Sn x Te wherein x can range from 0.0 to about 0.3.
Claim 8
Dependent Claim
76 words
The method of claim 4 wherein said sputtering target is prepared by reacting high purity constituents selected from the group consisting of (A) Pb, Sn and Te, and (b) PbTe and SnTe at elevated temperature in a vacuum zone to form Pb 1 -x Sn x Te wherein x is preselected to be between about 0 and 0.3, thereafter slowly cooling the resulting target and dimensioning and cleaning the target to provide a clean shiny surface.
Claim 9
Dependent Claim
45 words
The method of claim 5 wherein said target forming reaction is effected at about 1000° C. for about 6 hours, wherein said cooling is effected at a specified rate between about 200° and 400° C./hr and wherein said dimensioning is effected by lapping said target.
Claim 10
Dependent Claim
54 words
The method of claim 1 wherein said sputtering comprises supported discharge sputtering, wherein high purity argon is introduced into said reaction zone to about 0.5-5 μm after said zone has been evacuated to at least about 4× 10 - 7 torr, and wherein said sputtering target is conductively mounted on a cooled target holder.
Claim 11
Dependent Claim
44 words
The method of claim 7 wherein said target holder has a voltage applied which is variable to about 10 KV maximum with a resulting plasma current of 50 ma capacity, and wherein said film deposition rate is controlled by said target voltage and current.
Claim 12
Dependent Claim
52 words
The method of claim 1 wherein said sputtering comprises ion beam sputtering, wherein high purity argon is injected into a duoplasmatron acceleration section and is ionized, accelerated through a voltage controllable in a range of about 0-30 KV, electrostatically focused, collimated, passed to a high vacuum zone, and impinged on said target.
Claim 13
Dependent Claim
47 words
The method of claim 9 wherein the background pressure is about 1× 10 - 8 torr, the working pressure is about 1.5× 10 - 7 torr and the target is Pb 1 -x Sn x Te wherein x is in a range between 0 and about 0.3.
Claim 14
Dependent Claim
16 words
The method of claim 1 wherein said substrate comprises (111) plane single crystal CaF 2 .
Claim 15
Independent Claim
16 words
The method of claim wherein said substrate comprises ( 111) plane single crystal BaF 2 .
Claim 16
Dependent Claim
17 words
The method of claim 1 wherein said substrate comprises ( 100) plane single crystal CaF 2 .
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-07-04 | 1981-01-03 | 1981-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-04 | 1985-01-03 | 1985-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-04 | 1989-01-03 | 1989-07-05 | $7700.00 | Window Closed / Lapsed |