US3514265A - Method of growing strain-free single crystals - Google Patents

Method of growing strain-free single crystals Download PDF

Info

Publication number
US3514265A
US3514265A US628795A US3514265DA US3514265A US 3514265 A US3514265 A US 3514265A US 628795 A US628795 A US 628795A US 3514265D A US3514265D A US 3514265DA US 3514265 A US3514265 A US 3514265A
Authority
US
United States
Prior art keywords
crucible
crystal
strain
single crystals
growth
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US628795A
Inventor
John R Pastore
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
US Department of Army
Original Assignee
US Department of Army
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by US Department of Army filed Critical US Department of Army
Application granted granted Critical
Publication of US3514265A publication Critical patent/US3514265A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B13/00—Single-crystal growth by zone-melting; Refining by zone-melting
    • C30B13/14—Crucibles or vessels
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B13/00—Single-crystal growth by zone-melting; Refining by zone-melting
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/12—Halides
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S117/00—Single-crystal, oriented-crystal, and epitaxy growth processes; non-coating apparatus therefor
    • Y10S117/90—Apparatus characterized by composition or treatment thereof, e.g. surface finish, surface coating

Definitions

  • This invention relates in general to a method of growing strain-free single crystals, and in particular to a method of growing strain-free small diameter single crystals in laser rod form.
  • Low threshold laser crystals must be highly perfect and strain free. For continuous wave operation, further threshold lowering and more effective cooling is achieved by the use of small diameter crystals.
  • a method presently used for the production of laser rods involves the growth of a large diameter crystal which is slowly grown over a period of many hours, cooled very slowly, annealed for days in special ambients to remove growth-induced strains, and finally machined to size. Such rods are still prone to fracture because of residual strain during the initial cool-down prior to laser oscillation tests.
  • the general object of this invention is to provide a method of growing a small diameter strain-free single crystal.
  • a particular object of this invention is to provide a method of growing these single crystals in laser rod form.
  • a still further object of this invention is to provide a method of growing a small diameter strain-free single crystal which eliminates the time consuming re quirement of annealing or after heating, necessary in conventional growth methods.
  • a high density, high purity crucible is filled with the powder to be grown.
  • the filled crucible is then capped with a vented plug and positioned within an RF heating coil contained in an evacuated furnace.
  • the powder is melted and the temperature increased to establish thermal equilibrium.
  • Crystal growth is then started by lowering the crucible through the RF coil at a prescribed rate, the lowering of the crucible being stopped after the melt has crystallized.
  • a furnace is fitted with a water cooled jacket 12 and evacuating means 14. Positioned within the furnace 10 in approximately the center thereof is a water cooled RF coil 16. A high density, high purity crucible 18 capped with a vented plug 20 is hung by crucible hanger 22 in such manner as to be passable through RF coil 16, as shown. An automatic 3,514,265 Patented May 26, 1970 ice lowering mechanism (indicated by the arrow) is operat1vely connected with crucible hanger 22 and serves to lower the crucible 18 through the RF coil 16.
  • a high density, high purity graphite crucible 18 having an outer diameter of about one inch and an inner diameter of about inch to form a bore is filled with a mixture of calcium fluoride powder or cadmium fluoride powder with 0.1 mole percent by weight of the total mix of dysprosium fluoride.
  • the crucible bore is then capped with a vented plug 20 to reduce the escape of calcium fluoride vapors and the entire assembly is placed in furnace 10 substantially as shown, the furnace being evacuated to 1O- to 10- torr. After the charge has been melted, the temperature is increased another C.
  • the growth of a single crystal is started by lowering the crucible through the RF coil 16 at a rate of about inch to about inch per hour. As shown, nucleation occurs at a point below RF coil 16. After the melt has crystallized, the lowering of the crucible 18 is'stopped. The temperature of the grown single crystal is decreased from the melting point to 300 C. by increments of about 100 C. per 5 minutes to eliminate the occurrence of strain in the last solidified portion of the crystal; then all power to the RF coil 16 is turned off. After two hours the furnace 10 is blanked off from the vacuum system 14 and the crucible is cooled at room temperature before its removal. The crystal is then easily freed from the crucible by gentle tapping.
  • the thick walled graphite crucible provides a large thermal mass which allows sudden fluctuations of energy input (due to line voltage variations) to be damped out before their effect can reach the growing crystal.
  • the large thermal mass and the low thermal conductivity of the graphite crucible in addition to the small crystal diameter, allow a planar growth interface which is the ideal situation for growth of single crystals.
  • any plane of the crucible passes through the RF coil, it continues to be heated by the RF field. As the flux lines fan out rapidly, the heating of the crucible tapers off gradually away from the coil. This tapering heat input helps to balance the radiative loss and produces a gradual, instead of an abrupt, temperature change in the crystal beyond the recrystallization isotherm.
  • the very gradual temperature decrease along the crucible means that the isotherms are perpendicular to the crucible axis and decrease in temperature away from the RF heater.
  • the radial heat loss from the crystal is almost eliminated and the major heat flow from the crystal is essentially in an axial direction away from the growth interface.
  • This one dimensional distribution of heat has been shown to be the most desirable condition for cooling a grown crystal.
  • the beneficial effect of the method of the invention is verified by substituting a thin-wall graphite crucible for the thick wall and keeping all other parameters constant for a growth run. Though the crystals grown in the thin-wall crucible are predominantly single, none are strain free.
  • the single crystals are grown according to the invention in a matter of hours. Except for cutting and polishing of the ends, they are in laser rod form.
  • a crucible of suitable RF susceptor type material and appropriate ambient are chosen for growth of other compounds or elements.
  • the length of the particular crucible used depends upon the length of the crystal desired and the limitations of the growth apparatus.
  • the ratio of the outer diameter to the inner diameter of the particular crucible used should be at least 8 to 1. Of course, the crucible used must not react with the material that you are attempting to grow and must not stick to it after freezing.
  • a more favorable method would be an automatic and continuous temperature decrease over a specified period of time.
  • the ideal case if furnace dimensions allowed, would be to have a crucible of sufiicient length, possibly 24 inches, with the crystal in the bottom lowered three inches through the RF coil until the top of the grown crystal was at 300 C. or less.
  • an appropriate atmosphere is chosen, such as an inert gas or nitrogen.
  • the RF coil can also be of sufficient length so that all the material not nucleated will be in a molten state.
  • the crystals were tested for lineage and singularity, by neans of a scanning Laue X-ray diffraction method, in which the crystal and film are translated together normal a stationary X-ray beam in the Laue arrangement. Fhe resulting photograph shows a series of lines which tre parallel to the direction of crystal translation. The .traightness of these lines is a measure of the crystalline )erfection. Imperfections such as lineage, mosaic struc ure, and grain boundaries, will be revealed as irregulariies and breaks in the lines. Representative patterns show hat the crystals grown by this technique have a high legree of perfection.
  • Dislocation counts for the unactivated crystals grown vy this method were 5.3 10 /sq. cm. compared to .4X10 /sq. cm. for the optical grade CaF (Harshaw Zhemical Co.) starting material.
  • a CaF zDy crystal, grown according to the invention s ends paralleled, polished, and silvered, then irradiated with electrons to convert the Dy to By was tested or laser oscillations.
  • the pulsed threshold for the crystal t 77 K. in a concentric head was 28 joules input to an T524 lamp.
  • Seeded 111 crystals have been grown by this lethod.
  • the easy cleavage ⁇ 111 ⁇ plane is perpendicular the crystal axis.
  • the ends of the crystal can be leaved ofl easily with a razor blade resulting in a laser ad with a Fabry-Perot geometry.
  • Method of growing small diameter strain-free single crystals including the steps of:
  • Method of growing small diameter strain-free single crystals including the steps of:

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)

Description

y 6, 1970 J. R. PASTORE 3,514,265
METHOD OF GROWING STRAIN-FREE SINGLE CRYSTALS Filed April 5, 1967 AUTOMATIC LOWERING MECHANISM FURNIIPCA i i I VACUUM SYSTEM 22 GRAPHITE UCIBLE [8 SOLID CHARGE MELT GROWTH INTERFACE -TO GROWING CRYSTAL I R.F. NUCLEATION POINT ,7 GENERATOR INVENTOR,
JOHN R. PASTORE.
0 W ATTORNEYS United States Patent 3,514,265 METHOD OF GROWING STRAIN-FREE SINGLE CRYSTALS John R. Pasture, Long Branch, NJ assignor to the United States of America as represented by the Secretary of the Army Filed Apr. 5, 1967, Ser. No. 628,795 Int. Cl. B01j 17/24; C01g 11/00; C01f 11/22 US. Cl. 23301 2 Claims ABSTRACT OF THE DISCLOSURE Small diameter, strain-free single crystals are grown from a melt of powder in a high density crucible having a high ratio of outer diameter to inner diameter by gradually lowering the crucible through an RF coil contained in an evacuated furnace.
BACKGROUND OF THE INVENTION This invention relates in general to a method of growing strain-free single crystals, and in particular to a method of growing strain-free small diameter single crystals in laser rod form.
Low threshold laser crystals must be highly perfect and strain free. For continuous wave operation, further threshold lowering and more effective cooling is achieved by the use of small diameter crystals. A method presently used for the production of laser rods involves the growth of a large diameter crystal which is slowly grown over a period of many hours, cooled very slowly, annealed for days in special ambients to remove growth-induced strains, and finally machined to size. Such rods are still prone to fracture because of residual strain during the initial cool-down prior to laser oscillation tests.
SUMMARY OF THE INVENTION The general object of this invention is to provide a method of growing a small diameter strain-free single crystal. A particular object of this invention is to provide a method of growing these single crystals in laser rod form. A still further object of this invention is to provide a method of growing a small diameter strain-free single crystal which eliminates the time consuming re quirement of annealing or after heating, necessary in conventional growth methods.
It has now been found that the. foregoing objectives can be attained by a method utilizing a high density, high purity crucible as hereinafter more fully described. According to the invention, a high density, high purity crucible is filled with the powder to be grown. The filled crucible is then capped with a vented plug and positioned within an RF heating coil contained in an evacuated furnace. The powder is melted and the temperature increased to establish thermal equilibrium. Crystal growth is then started by lowering the crucible through the RF coil at a prescribed rate, the lowering of the crucible being stopped after the melt has crystallized.
The invention can be best understood by referring to the accompanying drawing wherein there is shown a cross section of suitable apparatus for carrying out the invention.
BRIEF DESCRIPTION OF THE DRAWING Referring to the drawing, a furnace is fitted with a water cooled jacket 12 and evacuating means 14. Positioned within the furnace 10 in approximately the center thereof is a water cooled RF coil 16. A high density, high purity crucible 18 capped with a vented plug 20 is hung by crucible hanger 22 in such manner as to be passable through RF coil 16, as shown. An automatic 3,514,265 Patented May 26, 1970 ice lowering mechanism (indicated by the arrow) is operat1vely connected with crucible hanger 22 and serves to lower the crucible 18 through the RF coil 16.
DESCRIPTION OF THE PREFERRED EMBODIMENT In a specific embodiment of the invention, a high density, high purity graphite crucible 18 having an outer diameter of about one inch and an inner diameter of about inch to form a bore is filled with a mixture of calcium fluoride powder or cadmium fluoride powder with 0.1 mole percent by weight of the total mix of dysprosium fluoride. The crucible bore is then capped with a vented plug 20 to reduce the escape of calcium fluoride vapors and the entire assembly is placed in furnace 10 substantially as shown, the furnace being evacuated to 1O- to 10- torr. After the charge has been melted, the temperature is increased another C. After thermal equilibrium is established, the growth of a single crystal is started by lowering the crucible through the RF coil 16 at a rate of about inch to about inch per hour. As shown, nucleation occurs at a point below RF coil 16. After the melt has crystallized, the lowering of the crucible 18 is'stopped. The temperature of the grown single crystal is decreased from the melting point to 300 C. by increments of about 100 C. per 5 minutes to eliminate the occurrence of strain in the last solidified portion of the crystal; then all power to the RF coil 16 is turned off. After two hours the furnace 10 is blanked off from the vacuum system 14 and the crucible is cooled at room temperature before its removal. The crystal is then easily freed from the crucible by gentle tapping.
In the method as described above, the thick walled graphite crucible provides a large thermal mass which allows sudden fluctuations of energy input (due to line voltage variations) to be damped out before their effect can reach the growing crystal. The large thermal mass and the low thermal conductivity of the graphite crucible, in addition to the small crystal diameter, allow a planar growth interface which is the ideal situation for growth of single crystals. During growth, as any plane of the crucible passes through the RF coil, it continues to be heated by the RF field. As the flux lines fan out rapidly, the heating of the crucible tapers off gradually away from the coil. This tapering heat input helps to balance the radiative loss and produces a gradual, instead of an abrupt, temperature change in the crystal beyond the recrystallization isotherm. This residual RF heating, the large thermal mass, and low thermal conductivity of the thick wall graphite all contribute to the very gradual temperature change along the crucible. The very gradual temperature decrease along the crucible means that the isotherms are perpendicular to the crucible axis and decrease in temperature away from the RF heater. As a result, the radial heat loss from the crystal is almost eliminated and the major heat flow from the crystal is essentially in an axial direction away from the growth interface. This one dimensional distribution of heat has been shown to be the most desirable condition for cooling a grown crystal. The beneficial effect of the method of the invention is verified by substituting a thin-wall graphite crucible for the thick wall and keeping all other parameters constant for a growth run. Though the crystals grown in the thin-wall crucible are predominantly single, none are strain free.
The single crystals are grown according to the invention in a matter of hours. Except for cutting and polishing of the ends, they are in laser rod form. For growth of other compounds or elements, a crucible of suitable RF susceptor type material and appropriate ambient are chosen. The length of the particular crucible used depends upon the length of the crystal desired and the limitations of the growth apparatus. The ratio of the outer diameter to the inner diameter of the particular crucible used should be at least 8 to 1. Of course, the crucible used must not react with the material that you are attempting to grow and must not stick to it after freezing.
Then, too, rather than cool the crystal by the 100 C. per 5 minute increments as shown in the embodiment, a more favorable method would be an automatic and continuous temperature decrease over a specified period of time. The ideal case, if furnace dimensions allowed, would be to have a crucible of sufiicient length, possibly 24 inches, with the crystal in the bottom lowered three inches through the RF coil until the top of the grown crystal was at 300 C. or less. Depending on the crystalline or amorphous material to be grown, an appropriate atmosphere is chosen, such as an inert gas or nitrogen. The RF coil can also be of sufficient length so that all the material not nucleated will be in a molten state.
Several methods were used to evaluate the quality andproperties of the crystals grown. All cleaved easily on the {111} plane and resulted in flat surfaces free of :urvature which is a good indication of the absence of ;train. When the crystals were viewed through crossed polarizers no evidence of strain was seen. I
The crystals were tested for lineage and singularity, by neans of a scanning Laue X-ray diffraction method, in which the crystal and film are translated together normal a stationary X-ray beam in the Laue arrangement. Fhe resulting photograph shows a series of lines which tre parallel to the direction of crystal translation. The .traightness of these lines is a measure of the crystalline )erfection. Imperfections such as lineage, mosaic struc ure, and grain boundaries, will be revealed as irregulariies and breaks in the lines. Representative patterns show hat the crystals grown by this technique have a high legree of perfection.
Dislocation counts for the unactivated crystals grown vy this method were 5.3 10 /sq. cm. compared to .4X10 /sq. cm. for the optical grade CaF (Harshaw Zhemical Co.) starting material.
A CaF zDy crystal, grown according to the invention :s ends paralleled, polished, and silvered, then irradiated with electrons to convert the Dy to By was tested or laser oscillations. The pulsed threshold for the crystal t 77 K. in a concentric head was 28 joules input to an T524 lamp.
Seeded 111 crystals have been grown by this lethod. The easy cleavage {111} plane is perpendicular the crystal axis. Thus the ends of the crystal can be leaved ofl easily with a razor blade resulting in a laser ad with a Fabry-Perot geometry.
Consequently a suitably activated crystal, with cleaved nds, mounted in an outside mirror type laser head can e used for laser oscillations almost upon removal from 1e growth crucible.
This would eliminate the many steps and many hours :quired for slow crystal growth, slow cooldown, anneal- 4 ing, paralleling and polishing the ends and polishing the barrel of the laser crystal.
The foregoing description is to be considered merely as illustrative of the invention and not in limitation thereof.
What is claimed is:
1. Method of growing small diameter strain-free single crystals including the steps of:
(A) filling a high density, high purity graphite crucible having an outer diameter of about one inch and an inner diameter of about 4 inch with a mixture of calcium fluoride with about 0.1 mole percent by Weight of dysprosium fluoride,
(B) capping the filled crucible with a vented plug,
(C) positioning the filled crucible within an RF heating coil contained in an evacuated furnace,
(D) melting the crystalline powder,
(E) increasing the temperature to establish thermal equilibrium,
(F) starting crystal growth by lowering the crucible through the RF coil at a rate of about A; inch to about inch per hour, and
(G) stopping the lowering of the crucible after the melt has crystallized.
2. Method of growing small diameter strain-free single crystals including the steps of:
(A) filling a high density, high purity graphite crucible having an outer diameter of about one inch and an inner diameter of about inch with a mixture of calcium fluoride with about 0.1 mole percent by Weight of dysprosium fluoride,
(B) capping the filled crucible with a vented plug,
(C) positioning the filled crucible within an RF heating coil contained in an evacuated furnace,
(D) melting the crystalline powder,
(E) increasing the temperature to establish thermal equilibrium,
(F) starting crystal growth by lowering the crucible through the RF coil at a rate of about inch to about inch per hour, and
(G) stopping the lowering of the crucible after the melt has crystallized.
References Cited UNITED STATES PATENTS 3,033,659 5/1962 Fischer 23-295 3,139,653 7/1964 Orem 22-57 3,243,267 3/1966 Piper 23301 3,273,969 9/1966 Sirgo 23273 OTHER REFERENCES Chemie.-lng.-Techn., vol. 28, No. 5 (1956), p. 358.
NORMAN YUDKOFF, Primary Examiner R. T. FOSTER, Assistant Examiner US. Cl. X.R. 23-88, 273
US628795A 1967-04-05 1967-04-05 Method of growing strain-free single crystals Expired - Lifetime US3514265A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US62879567A 1967-04-05 1967-04-05

Publications (1)

Publication Number Publication Date
US3514265A true US3514265A (en) 1970-05-26

Family

ID=24520336

Family Applications (1)

Application Number Title Priority Date Filing Date
US628795A Expired - Lifetime US3514265A (en) 1967-04-05 1967-04-05 Method of growing strain-free single crystals

Country Status (1)

Country Link
US (1) US3514265A (en)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3628998A (en) * 1969-09-23 1971-12-21 Ibm Method for growth of a mixed crystal with controlled composition
US4040894A (en) * 1967-06-13 1977-08-09 Huguette Fumeron Rodot Process of preparing crystals of compounds and alloys
US4224100A (en) * 1978-06-16 1980-09-23 Litton Systems, Inc. Method and apparatus for making crystals
US4231776A (en) * 1975-07-22 1980-11-04 Battelle Memorial Institute Method for manufacturing a panel of anisotropic ceramic glass
WO1982002409A1 (en) * 1981-01-05 1982-07-22 Electric Co Western The method and apparatus for forming and growing a single crystal of a semiconductor compound
US4379733A (en) * 1981-10-02 1983-04-12 Hughes Aircraft Company Bicameral mode crystal growth apparatus and process
US4521272A (en) * 1981-01-05 1985-06-04 At&T Technologies, Inc. Method for forming and growing a single crystal of a semiconductor compound
US4545848A (en) * 1982-11-08 1985-10-08 Mcdonnell Douglas Corporation HCT Crystal growth method
US4578145A (en) * 1979-07-05 1986-03-25 U.S. Philips Corporation Method of making monocrystalline ternary semiconductor compounds
US4666681A (en) * 1983-06-06 1987-05-19 Commissariat A L'energie Atomique Apparatus for producing a monocrystal
US5178719A (en) * 1991-08-20 1993-01-12 Horiba Instruments, Inc. Continuous refill crystal growth method
US6309461B1 (en) * 1999-06-07 2001-10-30 Sandia Corporation Crystal growth and annealing method and apparatus
US6620347B1 (en) * 1999-10-06 2003-09-16 Coherent, Inc. Crystalline filters for ultraviolet light sensors
US20080264330A1 (en) * 2004-05-18 2008-10-30 Board Of Trustees Of The University Of Arkansas Production of nanostructure by curie point induction heating

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3033659A (en) * 1959-04-21 1962-05-08 Gen Electric Preparation of phosphor crystals
US3139653A (en) * 1959-08-06 1964-07-07 Theodore H Orem Apparatus for the growth of preferentially oriented single crystals of metals
US3243267A (en) * 1964-07-31 1966-03-29 Gen Electric Growth of single crystals
US3273969A (en) * 1963-12-05 1966-09-20 Philco Corp Apparatus for growing fluoride crystals

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3033659A (en) * 1959-04-21 1962-05-08 Gen Electric Preparation of phosphor crystals
US3139653A (en) * 1959-08-06 1964-07-07 Theodore H Orem Apparatus for the growth of preferentially oriented single crystals of metals
US3273969A (en) * 1963-12-05 1966-09-20 Philco Corp Apparatus for growing fluoride crystals
US3243267A (en) * 1964-07-31 1966-03-29 Gen Electric Growth of single crystals

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4040894A (en) * 1967-06-13 1977-08-09 Huguette Fumeron Rodot Process of preparing crystals of compounds and alloys
US3628998A (en) * 1969-09-23 1971-12-21 Ibm Method for growth of a mixed crystal with controlled composition
US4231776A (en) * 1975-07-22 1980-11-04 Battelle Memorial Institute Method for manufacturing a panel of anisotropic ceramic glass
US4224100A (en) * 1978-06-16 1980-09-23 Litton Systems, Inc. Method and apparatus for making crystals
US4578145A (en) * 1979-07-05 1986-03-25 U.S. Philips Corporation Method of making monocrystalline ternary semiconductor compounds
WO1982002409A1 (en) * 1981-01-05 1982-07-22 Electric Co Western The method and apparatus for forming and growing a single crystal of a semiconductor compound
US4404172A (en) * 1981-01-05 1983-09-13 Western Electric Company, Inc. Method and apparatus for forming and growing a single crystal of a semiconductor compound
US4521272A (en) * 1981-01-05 1985-06-04 At&T Technologies, Inc. Method for forming and growing a single crystal of a semiconductor compound
US4379733A (en) * 1981-10-02 1983-04-12 Hughes Aircraft Company Bicameral mode crystal growth apparatus and process
US4545848A (en) * 1982-11-08 1985-10-08 Mcdonnell Douglas Corporation HCT Crystal growth method
US4666681A (en) * 1983-06-06 1987-05-19 Commissariat A L'energie Atomique Apparatus for producing a monocrystal
US5178719A (en) * 1991-08-20 1993-01-12 Horiba Instruments, Inc. Continuous refill crystal growth method
US6309461B1 (en) * 1999-06-07 2001-10-30 Sandia Corporation Crystal growth and annealing method and apparatus
US6620347B1 (en) * 1999-10-06 2003-09-16 Coherent, Inc. Crystalline filters for ultraviolet light sensors
US20050034655A1 (en) * 1999-10-06 2005-02-17 Lo Iacono Dominic N. Crystalline filters for ultraviolet sensors
US6917042B2 (en) 1999-10-06 2005-07-12 Vloc Incorporated Crystalline filters for ultraviolet sensors
US20080264330A1 (en) * 2004-05-18 2008-10-30 Board Of Trustees Of The University Of Arkansas Production of nanostructure by curie point induction heating

Similar Documents

Publication Publication Date Title
US3514265A (en) Method of growing strain-free single crystals
US6969502B2 (en) Method and device for growing large-volume oriented monocrystals
US4038201A (en) Polycrystalline bodies and means for producing them
Bleay et al. The growth of single crystals of some organic compounds by the Czochralski technique and the assessment of their perfection
US3997853A (en) Chromium-doped beryllium aluminate lasers
US4312700A (en) Method for making silicon rods
Iseler Thermal expansion and seeded Bridgman growth of AgGaSe2
US3715194A (en) Melt grown alumina crystals and process therefor
US2890139A (en) Semi-conductive material purification method and apparatus
US3033659A (en) Preparation of phosphor crystals
US4251315A (en) Method of growing metal halide and chalcogenide crystals for use as infrared windows
Shih et al. Czochralski growth of tellurium single crystals
US4199396A (en) Method for producing single crystal gadolinium gallium garnet
Feigelson et al. Solution growth of CdGeAs2
JPH0789797A (en) Production of terbium aluminum garnet single crystal
USRE31057E (en) Chromium-doped beryllium aluminate lasers
JPH054895A (en) Production of single crystal and apparatus therefor
JPH0244798B2 (en)
US5372088A (en) Crystal growth method and apparatus
GB1565407A (en) Method for producing single crystal gadolinium gallium
US4234376A (en) Growth of single crystal beryllium oxide
US4540550A (en) Apparatus for growing crystals
US4695347A (en) Process for the formation of single crystals from the gas phase
JPS60122791A (en) Pulling up method of crystal under liquid sealing
Khanna et al. Growth of low dislocation density single crystals of nickel