US4567849A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dipping liquid phase epitaxy for HgCdTe
Assignee: DRS Infrared Technologies LP
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Filing: 1984-05-07
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Granted: 1986-02-04
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Expires: 2004-05-07
Abstract
Abstract For HgCdTe liquid phase epitaxy (LPE), in situ differential thermal analysis apparatus is used to precisely monitor the liquidus temperature of each HgCdTe melt. The neutral body, e.g. a slug of copper enclosed in a silica ampoule, is placed near the LPE reactor in a furnace. During heating or cooling, differential sensing of a pair of thermocouples (in the melt and in the neutral body) will show an accelerated change at transformation points, since at these points the temperature of the melt will be changed by the energy of the physical change, while that of the neutral body remains subject only to passive heat transfer. Thus, the actual liquidus temperature of each melt can be measured with extreme precision, and isothermal or programmed cooling methods of LPE can be precisely and reliably controlled under production conditions.
Inventors
- 👤 Chang-Feng Wan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:43
CPC Classifications
C; C30; C30B; C30B19/00; C30B19/02; C30B29/00; C30B29/10; C30B29/46; C30B29/48
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
147 words
An apparatus for HgCdTe liquid phase epitaxial growth on a substrate, comprising: (a) a sealed vessel; (b) reactor means within said sealed vessel, for containing an HgCdTe melt; and (c) substrate holder means, extending within said sealed vessel, for holding a substrate and immersing said substrate in a melt within said reactor means, said substrate holder means including a housing for pivotally securing a substrate support thereto, said substrate support for securing the substrate thereto and in a normally vertical position, and means in said housing and axially movable relative thereto for rotating said support to a horizontal position; and a neutral body adjacent to said reactor within said vessel; first and second temperature sensing elements, said first temperature sensing element being within said reactor, and said second temperature sensing element being within said neutral body; means for differentially sensing said first and second temperature sensing elements.
Claim 2
Independent Claim
147 words
An apparatus for HgCdTe liquid phase epitaxial growth on a substrate, comprising: (a) a sealed vessel; (b) reactor means within said sealed vessel, for containing an HgCdTe melt; and (c) substrate holder means, extending within said sealed vessel, for holding a substrate and immersing said substrate in a melt within said reactor means, said substrate holder means including a housing for pivotally securing a substrate support thereto, said substrate support for securing the substrate thereto and in a normally vertical position, and means in said housing and axially movable relative thereto for rotating said support to a horizontal position; and a neutral body adjacent to said reactor within said vessel; first and second temperature sensing elements, said first temperature sensing element being within said reactor, and said second temperature sensing element being within said neutral body; means for differentially sensing said first and second temperature sensing elements.
Claim 3
Dependent Claim
19 words
An apparatus as set forth in claim 1 wherein said substrate support has a density less than about 6.8.
Claim 4
Dependent Claim
17 words
An apparatus as set forth in claim 2 wherein said substrate support is formed of fused quartz.
Claim 5
Dependent Claim
42 words
An apparatus as set forth in claim 3 wherein said housing is in the form of a sleeve and said means for rotating is a shaft movable axial of and within said sleeve to rotate said substrate holder to said horizontal position.
Claim 6
Dependent Claim
23 words
An apparatus as set forth in claim 4 further including a paddle at the end region of said shaft immersed in said melt.
Claim 7
Dependent Claim
42 words
An apparatus as set forth in claim 2 wherein said housing is in the form of a sleeve and said means for rotating is a shaft movable axial of and within said sleeve to rotate said substrate holder to said horizontal position.
Claim 8
Dependent Claim
23 words
An apparatus as set forth in claim 6 further including a paddle at the end region of said shaft immersed in said melt.
Claim 9
Dependent Claim
13 words
The apparatus of claim 1, wherein said sealed vessel comprises a quartz tube.
Claim 10
Dependent Claim
24 words
The apparatus of claim 1, wherein said reactor means further comprises a cover disposed on said reactor means to exclude falling droplets of mercury.
Claim 11
Dependent Claim
65 words
An apparatus as set forth in claim 1 further including a neutral body adjacent to said reactor within said vessel, the temperature sensing elements being first and second thermocouple elements, said first thermocouple element being within said melt and said second thermocouple element being within said neutral body and means for sensing said first thermocouple and for differentially sensing said first and second thermocouple elements.
Claim 12
Dependent Claim
17 words
An apparatus as set forth in claim 1 wherein said substrate support is formed of fused quartz.
Claim 13
Dependent Claim
42 words
An apparatus as set forth in claim 11 wherein said housing is in the form of a sleeve and said means for rotating is a shaft movable axial of and within said sleeve to rotate said substrate holder to said horizontal position.
Claim 14
Dependent Claim
23 words
An apparatus as set forth in claim 12 further including a paddle at the end region of said shaft immersed in said melt.
Claim 15
Dependent Claim
42 words
An apparatus as set forth in claim 1 wherein said housing is in the form of a sleeve and said means for rotating is a shaft movable axial of and within said sleeve to rotate said substrate holder to said horizontal position.
Claim 16
Dependent Claim
23 words
An apparatus as set forth in claim 14 further including a paddle at the end region of said shaft immersed in said melt.
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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) | 1989-02-03 | 1989-08-05 | 1990-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-03 | 1993-08-05 | 1994-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-03 | 1997-08-05 | 1998-02-04 | $7700.00 | Window Closed / Lapsed |