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US4743310A Expired / Lapsed US ⏱️ 0.0 years remaining

HGCDTE epitaxially grown on crystalline support

Assignee: Lockheed Martin Tactical Systems Inc
•
Filing: 1987-02-02
•
Granted: 1988-05-10
•
Expires: 2007-02-02
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Abstract

Abstract A layer of HgCdTe (15) is epitaxially grown on a crystalline support (10). A single crystal CdTe substrate (5) is first epitaxially grown to a thickness of between 1 micron and 5 microns onto the support (10). Then a HgTe source (3) is spaced from the CdTe substrate (5) a distance of between 0.1 mm and 10 mm. The substrate (5) and source (3) are heated together in a thermally insulating, reusable ampoule (17) within a growth temperature range of between 500° C. and 625° C. for a growth time of between 5 minutes and 13 hours. In a first growth step embodiment, the source (3) and substrate (5) are non-isothermal. In a second growth step embodiment, the source (3) and substrate (5) are isothermal. Then an optional interdiffusion step is performed, in which the source (3) and substrate (5) are cooled within a temperature range of between 400° C. and 500° C. for a time of between 1 hour and 16 hours. Means are disclosed for preventing contamination of the reactants during HgTe (3) synthesis, and for polishing the finished HgCdTe layer (15).

Inventors

  • 👤 Robert E. Kay
  • 👤 Hakchill Chan
  • 👤 Fred Ju
  • 👤 Burton A. Bray

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 11:31
CPC Classifications
C; C30; C30B; C30B25/00; C30B25/02; C30B25/22; C30B29/00; C30B29/10; C30B29/46; C30B29/48; H; H10; H10P; H10P14/00; H10P14/20; H10P14/22; H10P14/29; H10P14/2901; H10P14/2913; H10P14/2917; H10P14/32; H10P14/3202; H10P14/3224; H10P14/3232; H10P14/34; H10P14/3402; H10P14/3424; H10P14/3432; Y; Y10; Y10S; Y10S148/00; Y10S148/064; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12528

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 53 words
A layer of Hg 1-x Cd x Te epitaxially grown and firmly bonded onto a crystalline support other than cadmium telluride, wherein: the Hg 1-x Cd x Te is a single vertically and laterally uniform layer of a single pure carbonless composition having a thickness of 0.7 microns to 30 microns; and 0<x<1.
Claim 2
Dependent Claim 53 words
A layer of Hg 1-x Cd x Te epitaxially grown and firmly bonded onto a crystalline support other than cadmium telluride, wherein: the Hg 1-x Cd x Te is a single vertically and laterally uniform layer of a single pure carbonless composition having a thickness of 0.7 microns to 30 microns; and 0<x<1.
Claim 3
Dependent Claim 15 words
The layer of claim 1 wherein x is preselected to be between 0.18 and 0.5.
Claim 4
Dependent Claim 92 words
The layer of claim 1 wherein said layer is formed by a process in which a CdTe substrate between 1 micron and 5 microns thick is epitaxially grown onto the crystalline support; a HgTe source and the CdTe substrate are spaced apart from each other by a distance of between 0.1 mm and 10 mm; and a growth step is performed, in which the HgTe and CdTe are heated within a growth temperature range of between 500° C. and 625° C. for a growth time of between 5 minutes and 13 hours.
Claim 5
Dependent Claim 24 words
The layer of claim 3 wherein the temperatures of the HgTe and CdTe are each kept constant at all times during the growth step.
Claim 6
Dependent Claim 17 words
The layer of claim 3 wherein the CdTe is hotter than the HgTe during the growth step.
Claim 7
Dependent Claim 47 words
The layer of claim 3 wherein, subsequent to the growth step, an interdiffusion step is performed in which the HgTe and CdTe are cooled within an interdiffusion temperature range of between 400° C. and 500° C. for an interdiffusion time of between 1 hour and 16 hours.
Claim 8
Dependent Claim 49 words
The layer of claim 1 wherein the crystalline support initially supports epitaxial growth of single crystal CdTe thereon, and is stable to temperatures at least as high as those encountered in a subsequent heating step in which the single crystal CdTe is converted to Hg 1-x Cd x Te.
Claim 9
Dependent Claim 29 words
The layer of claim 7 wherein the crystalline support is transparent in at least a portion of the infrared spectrum having a wavelength between 1 micron and 25 microns.
Claim 10
Dependent Claim 26 words
The layer of claim 7 wherein the crystalline support is fabricated of a material from the class of materials consisting of sapphire, GaAs, Si, and InSh.

References Cited (Backward Citations)

US3622405A Cited
US3884788A Cited
US3902924A Cited
US4418096A Cited
US4435224A Cited
US4650539A Cited
US4642142A Cited
US4487813A Cited
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US4487640A Cited
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US4648917A Cited
US4655848A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1991-05-10 1991-11-09 1992-05-10 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1995-05-10 1995-11-09 1996-05-10 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1999-05-10 1999-11-09 2000-05-10 $7700.00 Window Closed / Lapsed

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