Patent USH894H successfully refreshed from Google Patents.
USH894H
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US
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IR detector structure and method of making
Assignee: United States Department of the Army
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Filing: 1989-07-13
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Granted: 1991-03-05
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Expires: 2009-07-13
Abstract
Abstract An IR detector structure is made from a CdTe substrate by polishing the C subtrate, and transferring the cleaned substrate to a chamber for successive epitaxial growth of HgCdTe and CdTe layers insitu without removal reducing contamination at the interfaces due to exposure to the atmosphere.
Inventors
- 👤 James Halvis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:15
CPC Classifications
H; H10; H10F; H10F30/00; H10F30/20; H10F30/21; H10F30/28; H10F30/2823; H10F71/00; H10F71/125; H10F71/1253; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/543; Y02P; Y02P70/00; Y02P70/50
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
136 words
Method of making an IR detector structure from a CdTe substrate, said method including the steps of: (A) polishing the CdTe substrate (B) transferring the cleaned substrate to a chamber for successive epitaxial growth of HgCdTe and CdTe layers insitu without removal reducing contamination at the interfaces due to exposure to the atmosphere, (C) growing an epitaxial layer of a narrow gap HgCdTe of about 10 μm in thickness onto the CdTe substrate (D) growing an epitaxial layer of wide gap HgCdTe of about 0.5 μm in thickness onto the narrow gap layer, (E) growing an electrical insulating epitaxial layer of CdTe of about 0.1 to 0.2 μm in thickness onto the wide gap layer of HgCdTe, and (F) growing an epitaxial transparent HgCdTe gate layer of about 0.5 μm in thickness onto the CdTe layer.
Claim 2
Dependent Claim
136 words
Method of making an IR detector structure from a CdTe substrate, said method including the steps of: (A) polishing the CdTe substrate (B) transferring the cleaned substrate to a chamber for successive epitaxial growth of HgCdTe and CdTe layers insitu without removal reducing contamination at the interfaces due to exposure to the atmosphere, (C) growing an epitaxial layer of a narrow gap HgCdTe of about 10 μm in thickness onto the CdTe substrate (D) growing an epitaxial layer of wide gap HgCdTe of about 0.5 μm in thickness onto the narrow gap layer, (E) growing an electrical insulating epitaxial layer of CdTe of about 0.1 to 0.2 μm in thickness onto the wide gap layer of HgCdTe, and (F) growing an epitaxial transparent HgCdTe gate layer of about 0.5 μm in thickness onto the CdTe layer.
Claim 3
Dependent Claim
25 words
Method according to claim 1 where in step (A) the CdTe substrate is polished with a light surface etch in a dilute solution of bromine/methanol.
Claim 4
Dependent Claim
24 words
Method according to claim 1 where in step (B) the chamber for epitaxial growth is selected from the group consisting of MBE and MOCVD.
Claim 5
Dependent Claim
13 words
Method according to claim 3 where in step (B) the chamber is MBE.
Claim 6
Dependent Claim
12 words
Method according to claim 3 wherein step (B) the chamber is MOCVD.
Claim 7
Dependent Claim
71 words
Method according to claim 4 wherein MBE epitaxial growth is achieved by codeposition of mercury, tellurium and cadmium telluride onto the substrate which is heated to about 200° C. and wherein deposition rate and composition are controlled by adjusting the temperature of the effusion source cells for the Hg, Te and CdTe, approximate temperature being about 700° C. for CdTe, about 400° C. for Te, and about 200° C. for Hg.
Claim 8
Dependent Claim
39 words
Method according to claim 5 wherein MOCVD epitaxial growth is achieved on substrates heated to about 400° C. by chemical vapor deposition, typical gas sources being demethylcadmium for Cd and diethyltelluride for Te, elemental mercury being provided by evaporation.
Claim 9
Dependent Claim
78 words
An IR detector structure, said structure comprising a cadmium telluride substrate, an epitaxial layer of narrow gap HgCdTe on said substrate and wherein said epitaxial layer has been grown insitu, a wide gap epitaxial layer of HgCdTe on said narrow gap layer and wherein said wide gap layer has been grown insitu, a CdTe electrical insulating layer epitaxially grown insitu on said wide gap layer, and a transparent HgCdTe gate layer grown epitaxially, insitu, on said CdTe layer.
Claim 10
Dependent Claim
78 words
An IR detector structure, said structure comprising a cadmium telluride substrate, an epitaxial layer of narrow gap HgCdTe on said substrate and wherein said epitaxial layer has been grown insitu, a wide gap epitaxial layer of HgCdTe on said narrow gap layer and wherein said wide gap layer has been grown insitu, a CdTe electrical insulating layer epitaxially grown insitu on said wide gap layer, and a transparent HgCdTe gate layer grown epitaxially, insitu, on said CdTe layer.
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) | 1994-03-04 | 1994-09-03 | 1995-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-03-04 | 1998-09-03 | 1999-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-03-04 | 2002-09-03 | 2003-03-05 | $7700.00 | Window Closed / Lapsed |