Patent US3929556A successfully refreshed from Google Patents.
US3929556A
Expired / Lapsed
US
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Nucleating growth of lead-tin-telluride single crystal with an oriented barium fluoride substrate
Assignee: Cincinnati Electronics Corp
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Filing: 1974-02-19
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Granted: 1975-12-30
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Expires: 1994-02-19
Abstract
Abstract A method and apparatus for growing a single crystal boule of lead-tin-telluride involves nucleating growth on a crystallographically oriented barium fluoride substrate by a vapor transport expitaxy technique. A charge of polycrystalline lead-tin-telluride is positioned so it is axially spaced from the substrate within an evacuated ampoule. The charge is heated so that it vaporizes and the vapor therefrom is collected and directed to a region of the substrate via a funnel shaped conduit interposed between the substrate and the charge having a large mouth for receiving the vapor. The portion of the conduit abutting the substrate may be either conical or cylindrical to control the cross-sectional area of the crystal. The substrate is maintained cooler than the charge so that the vapor migrates within the conduit to the substrate and is deposited thereon in aligned crystalline fashion. Crystal growth is confined within the conduit whereby the final crystal boule assumes the shape of the interior of the conduit. The conduit portion abutting the substrate defines the area of the substrate initially exposed to the vapor.
Inventors
- 👤 Raghvendra K Pandey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 13:39
CPC Classifications
C; C30; C30B; C30B23/00; Y; Y10; Y10S; Y10S117/00; Y10S117/901; Y10S117/902; Y10S117/915; Y10S148/00; Y10S148/063; Y10S148/064; Y10S148/145; Y10S148/15; Y10S438/00; Y10S438/93
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
58 words
THE METHOD OF PRODUCING A SINGLE CRYSTAL OF LEAD-TIN-TELLURIDE COMPRISING DEPOSITING HOMOGENEOUS LEAD-TIN-TELLURIDE VAPOR ON A CRYSTALLOGRIPHICALLY ORIENTED BARIUM FLUORIDE SUBSTRATE TO FORM A GROWING BULK SINGLE CRYSTAL HAVING THE SAME ORIENTATION AS THE SUBSTRATE AND REMOVING THE SINGLE CRYSTAL FROM THE SUBSTRATE AFTER SUFFICIENT GROWTH OF THE SINGLE CRYSTAL HAS OCCURED FOR THE CRYSTAL TO BE SELF-SUPPORTING.
Claim 2
Independent Claim
58 words
THE METHOD OF PRODUCING A SINGLE CRYSTAL OF LEAD-TIN-TELLURIDE COMPRISING DEPOSITING HOMOGENEOUS LEAD-TIN-TELLURIDE VAPOR ON A CRYSTALLOGRIPHICALLY ORIENTED BARIUM FLUORIDE SUBSTRATE TO FORM A GROWING BULK SINGLE CRYSTAL HAVING THE SAME ORIENTATION AS THE SUBSTRATE AND REMOVING THE SINGLE CRYSTAL FROM THE SUBSTRATE AFTER SUFFICIENT GROWTH OF THE SINGLE CRYSTAL HAS OCCURED FOR THE CRYSTAL TO BE SELF-SUPPORTING.
Claim 3
Dependent Claim
99 words
The method of claim 1 wherein said depositing step comprises heating a solid charge of lead-tin-telluride to a first temperature at which the charge will vaporize, heating the substrate to a temperature slightly less than the first charge, and heating the intervening volume between the substrate and volume so that a monotonic temperature variation exists between the substrate and source, the intervening volume being small enough in cross section to confine the vapor, the temperature in the volume and the temperature difference between the substrate and source being such that the vapor migrates toward and condenses on the substrate.
Claim 4
Dependent Claim
41 words
The method of claim 2 wherein the vapor is transported to only a region of said substrate which is sufficiently small to nucleate only a single lead-tin-telluride crystal domain, said region having a largest dimension ranging between 4 and 10 millimeters.
Claim 5
Dependent Claim
32 words
The method of claim 3 further comprising transporting the vapor to a region larger than and including the instantaneous area of said growing crystal whereby said growing crystal grows in cross-sectional area.
Claim 6
Dependent Claim
36 words
The method of claim 2 wherein said depositing is done while maintaining the temperature of the substrate in the range of 4*-10*C. less than the temperature of the charge whereby the vapor migrates to the substrate.
Claim 7
Dependent Claim
26 words
The method of claim 5 wherein said heating maintains the temperature of said charge at a temperature selected from the range of 840* to 875* C.
Claim 8
Dependent Claim
47 words
The method of claim 2 further comprising providing a conduit abutting the substrate and wherein said depositing step includes directing said vapor through said conduit onto said substrate region, said conduit having a cross section to confine the flow of said vapor between the charge and substrate.
Claim 9
Dependent Claim
12 words
The method of claim 7 wherein said conduit comprises a straight cylinder.
Claim 10
Dependent Claim
32 words
The method of claim 8 wherein said cylinder is circular having a diameter of approximately 1 centimeter for exposing a 1 centimeter diameter region of the substrate to deposition of said vapor.
Claim 11
Dependent Claim
29 words
The method of claim 2 wherein the vaporized charge is vaporized and deposited onto said substrate in an ampoule having a pressure of approximately 10 6 millimeters of mercury.
Claim 12
Dependent Claim
26 words
The method of claim 10 wherein the charge is funneled onto the substrate to a region having its greatest cross-sectional dimension between 4 and 10 millimeters.
Claim 13
Dependent Claim
36 words
The method of claim 11 wherein said depositing is done while maintaining the temperature of the substrate in the range of 4*-10*C. less than the temperature of the charge whereby the vapor migrates to the substrate.
Claim 14
Dependent Claim
23 words
The method of claim 10 wherein the solid charge is isothermally heated throughout its volume to provide uniform mobility to the vapor molecules.
Claim 15
Dependent Claim
33 words
The method of claim 13 further including the step of heat sinking the substrate while the vapor is deposited thereon so as to provide sufficient thermal inertia to maintain the substrate temperature constant.
Claim 16
Dependent Claim
36 words
The method of claim 14 wherein said depositing is done while maintaining the temperature of the substrate in the range of 4*-10*C. less than the temperature of the charge whereby the vapor migrates to the substrate.
Claim 17
Dependent Claim
36 words
The method of claim 13 wherein said depositing is done while maintaining the temperature of the substrate in the range of 4*-10*C. less than the temperature of the charge whereby the vapor migrates to the substrate.
Claim 18
Dependent Claim
33 words
The method of claim 10 further including the step of heat sinking the substrate while the vapor is deposited thereon so as to provide sufficient thermal inertia to maintain the substrate temperature constant.
Claim 19
Dependent Claim
36 words
The method of claim 17 wherein said depositing is done while maintaining the temperature of the substrate in the range of 4*-10*C. less than the temperature of the charge whereby the vapor migrates to the substrate.
Claim 20
Dependent Claim
36 words
The method of claim 10 wherein said depositing is done while maintaining the temperature of the substrate in the range of 4*-10*C. less than the temperature of the charge whereby the vapor migrates to the substrate.
Claim 21
Dependent Claim
23 words
The method of claim 2 wherein the solid charge is isothermally heated throughout its volume to provide uniform mobility to the vapor molecules.
Claim 22
Dependent Claim
33 words
The method of claim 20 further including the step of heat sinking the substrate while the vapor is deposited thereon so as to provide sufficient thermal inertia to maintain the substrate temperature constant.
Claim 23
Dependent Claim
36 words
The method of claim 21 wherein said depositing is done while maintaining the temperature of the substrate in the range of 4*-10*C. less than the temperature of the charge whereby the vapor migrates to the substrate.
Claim 24
Dependent Claim
36 words
The method of claim 20 wherein said depositing is done while maintaining the temperature of the substrate in the range of 4*-10*C. less than the temperature of the charge whereby the vapor migrates to the substrate.
Claim 25
Dependent Claim
33 words
The method of claim 2 further including the step of heat sinking the substrate while the vapaor is deposited thereon so as to provide sufficient thermal inertia to maintain the substrate temperature constant.
Claim 26
Dependent Claim
36 words
The method of claim 24 wherein said depositing is done while maintaining the temperature of the substrate in the range of 4*-10*C. less than the temperature of the charge whereby the vapor migrates to the substrate.
References Cited (Backward Citations)
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US3725135A
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US3551117A
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US3716424A
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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) | 1978-12-29 | 1979-06-30 | 1979-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-29 | 1983-06-30 | 1983-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-29 | 1987-06-30 | 1987-12-30 | $7700.00 | Window Closed / Lapsed |