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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 05:56
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
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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) 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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