Includin A Solid Member Other Than Seed Or Product Contacting The Liquid (e.g., Crucible, Immersed Heating Element) Patents (Class 117/220)
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Patent number: 8926751Abstract: The present invention relates to a gas flow guiding device for use in a crystal-growing furnace. The gas flow guiding device has an insulation layer enclosing a crucible, a gas inlet mounted in the upper insulation layer, and a gas exit formed in the lateral insulation layer. A plurality of guide plates are radially arranged around the opening of the gas inlet, so that the free surface of the melt is blown by the guided gas flow in such a manner that the gas flow takes the impurity away from the free surface efficiently. As a result, the crystal ingot obtained by solidifying the melt will exhibit a reduced concentration of impurities and an improved crystal quality.Type: GrantFiled: December 2, 2010Date of Patent: January 6, 2015Assignee: National Central UniversityInventors: Jyh-Chen Chen, Ying-Yang Teng, Chung-Wei Lu, Hsueh-I Chen
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Publication number: 20140338591Abstract: Provide a converging mirror-based furnace for heating a target by way of reflecting from a reflecting mirror unit the light emitted from a light source and then irradiating a target with the reflected light, wherein said target-heating converging-light furnace is such that: the reflecting mirror unit comprises a primary reflecting mirror and secondary reflecting mirror; the light emitted from the light source is reflected sequentially by the primary reflecting mirror and secondary reflecting mirror and then irradiated onto the target; and the light reflected by the secondary reflecting mirror and irradiated onto the target surface is not perpendicular to the target surface. Based on the above, a system that uses converged infrared light to provide heating can be made smaller while keeping its heating performance intact, even when the system uses a revolving ellipsoid.Type: ApplicationFiled: November 30, 2012Publication date: November 20, 2014Applicant: NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGYInventors: Shinichi Ikeda, Shiro Hara, Takanori Mikahara, Hitoshi Habuka, Sommawan Khumpuang
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Patent number: 8753446Abstract: Evaporated matters and reaction products produced in a furnace can be exhausted without contacting with a graphite crucible and a heater, and an exhaust pipe per se can be maintained at a high temperature to suppress the deposition and condensation of the evaporated matters and reaction products, whereby the clogging of the exhaust pipe is prevented, in addition, a conversion of the exhaust pipes per se into SiC is suppressed to improve the durability of the exhaust pipe, and the change in thermal expansion coefficient is suppressed, whereby a thermal single crystal can be pulled up in high quality. Further, the exhaust pipe is formed of a small number of materials to reduce a production cost. A heat shield (12) made of a heat insulating material is provided outside a heater (6), and a plurality of exhaust pipes (20) are provided between the heater (6) and the heat shield (12).Type: GrantFiled: December 13, 2005Date of Patent: June 17, 2014Assignee: Sumco Techxiv Kabushiki KaishaInventors: Akiko Noda, Tetsuhiro IIda
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Patent number: 8728238Abstract: This invention includes a system and a method for growing crystals including a batch auto-feeding mechanism. The proposed system and method provide a minimization of compositional segregation effect during crystal growth by controlling growth rate involving a high-temperature flow control system operable in an open and a closed loop crystal growth process. The ability to control the growth rate without corresponding loss of volatilize-able elements enables significantly improvement in compositional homogeneity and a consequent increase in crystal yield. This growth system and method can be operated in production scale, simultaneously for a plurality of growth crucibles to further the reduction of manufacturing costs, particularly for the crystal materials of binary or ternary systems with volatile components, such as Lead (Pb) and Indium (In).Type: GrantFiled: August 1, 2013Date of Patent: May 20, 2014Assignee: H.C. Materials CorporationInventors: Pengdi Han, Jian Tian
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Publication number: 20140083351Abstract: The present invention relates to a process for the growth of a crystalline solid by inching then cooling a crystallization material (2), in which the crystallization material (2) spread over a support is melted in the operating region (4) of a heat source. According to this process: outside of the operating region, the crystallization material (2) is spread over at least two areas of different compositions (31, 32, 33, 34, 33), and the crystallization material (2) being spread over a length greater than the length of the operating region (4), a movement of the operating region (4) relative to the crystallization material (2) is carried out so as to place successively in the operating region (4) then outside of the operating region, portions of the crystallization material of different compositions. This process is used to manufacture laser crystals having a controlled spatial distribution of doping.Type: ApplicationFiled: May 22, 2012Publication date: March 27, 2014Applicant: ECOLE POLYTECHNIQUEInventors: Jean-Christophe Chanteloup, Narine Ananyan, Vladimir Gevorgyan, Mikayel Arzakantsyan
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Patent number: 8591648Abstract: A crystal growing system having multiple rotatable crucibles and using a temperature gradient method comprises a crystal furnace, a plurality of crucibles, a supporting device, and a temperature control device. The crystal furnace includes a furnace body, a heater, and a hearth, wherein the furnace body from outer to inner includes an outer shell, a fiber insulation layer, an insulation brick layer, and a refractory layer. The crucible supporting device includes an elevator, a plurality of crucible guiding tubes, and a plurality of tube holders each capable of supporting a crucible guiding tube, a moving device that is connected to the elevator, a motor with electrical power that is connected to the moving device, wherein there is an affixing device between each pair of guiding tube and guiding tube holder. Each crucible is located in a corresponding crucible guiding tube. The crucible supporting device is a rotatable device.Type: GrantFiled: December 27, 2007Date of Patent: November 26, 2013Inventor: Youbao Wan
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Patent number: 8580036Abstract: The method and apparatus includes a vessel having a bottom and sidewalls arranged to house the material in a molten state. A temperature controlled horizontally oriented, cooling plate is movable into and out of the top of the molten material. When the cooling plate is lowered into the top of the melt, an ingot of solid silicon is solidified downwards.Type: GrantFiled: May 10, 2006Date of Patent: November 12, 2013Assignee: Elkem Solar ASInventor: Kenneth Friestad
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Patent number: 8535442Abstract: This invention includes a system and a method for growing crystals including a batch auto-feeding mechanism. The proposed system and method provide a minimization of compositional segregation effect during crystal growth by controlling growth rate involving a high-temperature flow control system operable in an open and a closed loop crystal growth process. The ability to control the growth rate without corresponding loss of volatilize-able elements enables significantly improvement in compositional homogeneity and a consequent increase in crystal yield. This growth system and method can be operated in production scale, simultaneously for a plurality of growth crucibles to further the reduction of manufacturing costs, particularly for the crystal materials of binary or ternary systems with volatile components, such as Lead (Pb) and Indium (In).Type: GrantFiled: July 12, 2007Date of Patent: September 17, 2013Assignee: H.C. Materials CorporationInventors: Pengdi Han, Jian Tian
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Patent number: 8349080Abstract: A micro-manipulator machine for harvesting and cryofreezing crystals for cryogenic storage and subsequent analysis includes a micropositioner mechanism for converting motions manually input to a position control knob to fractionally-scaled motions of a follower mechanism which includes a tool head support arm and tool head that releasably holds a filamentary polymer cryoloop for immersion into a liquid crystal growth media and extraction of a liquid drop containing a selected crystal from the media. A first automatic actuator mechanism orbits the tool head support arm, tool head, cryoloop, liquid drop and harvested crystal from a harvesting location to a retrieval location when the micropositioner input control arm has been moved manually away from the crystal harvesting location by the operator after extracting a crystal drop, and a second automatic actuator mechanism pivots the toll head into a flowing stream of a cryogenic gas to freeze the liquid drop and crystal.Type: GrantFiled: November 24, 2008Date of Patent: January 8, 2013Assignee: West Bond, Inc.Inventor: John C. Price
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Patent number: 8317919Abstract: An improved system based on the Czochralski process for continuous growth of a single crystal ingot comprises a low aspect ratio, large diameter, and substantially flat crucible, including an optional weir surrounding the crystal. The low aspect ratio crucible substantially eliminates convection currents and reduces oxygen content in a finished single crystal silicon ingot. A separate level controlled silicon pre-melting chamber provides a continuous source of molten silicon to the growth crucible advantageously eliminating the need for vertical travel and a crucible raising system during the crystal pulling process. A plurality of heaters beneath the crucible establish corresponding thermal zones across the melt. Thermal output of the heaters is individually controlled for providing an optimal thermal distribution across the melt and at the crystal/melt interface for improved crystal growth. Multiple crystal pulling chambers are provided for continuous processing and high throughput.Type: GrantFiled: February 25, 2005Date of Patent: November 27, 2012Assignee: Solaicx, Inc.Inventor: David L Bender
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Patent number: 8216369Abstract: A physical vapor transport system includes a growth chamber charged with source material and a seed crystal in spaced relation, and at least one capsule having at least one capillary extending between an interior thereof and an exterior thereof, wherein the interior of the capsule is charged with a dopant. Each capsule is installed in the growth chamber. Through a growth reaction carried out in the growth chamber following installation of each capsule therein, a crystal is formed on the seed crystal using the source material, wherein the formed crystal is doped with the dopant.Type: GrantFiled: October 5, 2009Date of Patent: July 10, 2012Assignee: II-VI IncorporatedInventors: Avinash K. Gupta, Edward Semenas, Ilya Zwieback, Donovan L. Barrett, Andrew E. Souzis
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Patent number: 8016944Abstract: Methods and apparatus for producing nanoparticles, including single-crystal semiconductor nanoparticles, are provided. The methods include the step of generating a constricted radiofrequency plasma in the presence of a precursor gas containing precursor molecules to form nanoparticles. Single-crystal semiconductor nanoparticles, including photoluminescent silicon nanoparticles, having diameters of no more than 10 nm may be fabricated in accordance with the methods.Type: GrantFiled: November 3, 2008Date of Patent: September 13, 2011Assignee: Regents of the University of MinnesotaInventors: Uwe Kortshagen, Elijah J. Thimsen, Lorenzo Mangolini, Ameya Bapat, David Jurbergs
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Patent number: 7955511Abstract: A silica glass crucible used for pulling up silicon single crystal at a high temperature. The silica glass crucible may have at least an outer surface of a wall part of the crucible covered with fine grooves having a length of less than 200 ?m, a width of less than 30 ?m and a depth of from more than 3 ?m to less than 30 ?m. The fine groves may be formed by carrying out a sand-blast treatment and a hydrofluoric acid etching and may exist on more than 10% of the outer surface of the crucible, and a sliding frictional coefficient of the outer surface of the crucible to a carbon at 1500° C. is more than 0.6.Type: GrantFiled: March 4, 2010Date of Patent: June 7, 2011Assignee: Japan Super Quartz CorporationInventors: Yoshiyuki Tsuji, Toshio Tsujimoto
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Patent number: 7811383Abstract: The device for production of a monocrystalline or a multicrystalline material blank, especially a silicon multicrystalline blank, using the VGF method has a crucible with a rectangular or square cross section. A flat heating device, especially a jacket heater, which generates an inhomogeneous temperature profile, is arranged around the crucible. This temperature profile corresponds to the temperature gradient formed in the center of the crucible. The heat output of the flat heating device decreases from the top to the bottom end of the crucible. The flat heating device includes parallel heating webs, which extend in a meandering course. The heat outputs from the heating webs differ according to their different conductor cross sections. To avoid local overheating in corner areas of the crucible, constrictions of the cross sections of the heating webs are provided at inversion zones of their meandering course.Type: GrantFiled: April 9, 2009Date of Patent: October 12, 2010Assignee: Schott AGInventors: Matthias Mueller, Markus Finkbeiner, Uwe Sahr, Ingo Schwirtlich, Michael Clauss
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Patent number: 7799131Abstract: The present invention provides a method for the continuous production of semiconductor ribbons by growth from a linear molten zone. The creation of the molten zone is achieved by application of an electric current, direct or alternating, parallel to the surface of the ribbon and perpendicular to the direction of growth, and intense enough to melt the said material, preferably using electrodes of the said material. The molten zone is fed by transference of the material, in the liquid state, from one or more reservoirs, where melting of the feedstock occurs. Preferably, the said electrodes and the said reservoir(s) are only constituted by the said material, thus avoiding contamination by foreign materials. The present invention is applicable, for example, in the industry of silicon ribbons production for photovoltaic application.Type: GrantFiled: April 15, 2004Date of Patent: September 21, 2010Assignee: Faculdade de Ciencias Da Universidade de LisboaInventors: António Vallêra, João Serra, Jorge Maia Alves, Miguel Brito, Roberto Gamboa, João Henriques
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Patent number: 7695787Abstract: To provide a silica glass crucible, wherein there are no problems of generating a sinking and buckling when said crucible is used for pulling up silicon single crystal at a high temperature. The silica glass crucible used for pulling up the silicon single crystal, wherein at least an outer surface of a wall part of the crucible is covered with fine grooves having a length of less than 200 ?m, a width of less than 30 ?m and a depth of from more than 3 ?m to less than 30 ?m. Preferably, said fine groves are formed by carrying out a sand-blast treatment and a hydrofluoric acid etching and exist on more than 10% of the outer surface of the crucible, and a sliding frictional coefficient of the outer surface of the crucible to a carbon at 1500 degree C. is more than 0.6.Type: GrantFiled: March 17, 2004Date of Patent: April 13, 2010Assignee: Japan Super Quartz CorporationInventors: Yoshiyuki Tsuji, Toshio Tsujimoto
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Patent number: 7625446Abstract: A capsule for containing at least one reactant and a supercritical fluid in a substantially air-free environment under high pressure, high temperature processing conditions. The capsule includes a closed end, at least one wall adjoining the closed end and extending from the closed end; and a sealed end adjoining the at least one wall opposite the closed end. The at least one wall, closed end, and sealed end define a chamber therein for containing the reactant and a solvent that becomes a supercritical fluid at high temperatures and high pressures. The capsule is formed from a deformable material and is fluid impermeable and chemically inert with respect to the reactant and the supercritical fluid under processing conditions, which are generally above 5 kbar and 550° C. and, preferably, at pressures between 5 kbar and 80 kbar and temperatures between 550 ° C. and about 1500° C.Type: GrantFiled: December 10, 2004Date of Patent: December 1, 2009Assignee: Momentive Performance Materials Inc.Inventors: Mark Philip D'Evelyn, Kristi Jean Narang, Robert Arthur Giddings, Steven Alfred Tysoe, John William Lucek, Suresh Shankarappa Vagarali, Robert Vincent Leonelli, Jr., Joel Rice Dysart
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Patent number: 7399360Abstract: Provided are a crucible which prevents polycrystal formation to easily allow growth of optical part material single crystals, and a single crystal growth method employing the crucible. The crucible has a smooth surface of about Rmax 3.2s as the surface roughness of the wall surface 1H, concave curved plane 1J, cone surface 1F and convex curved plane 1L of the starting material carrying section 1D and the wall surface 1K of the seed carrying section 1E, which constitute the inner surface of the crucible of a crucible body 1A.Type: GrantFiled: June 18, 2004Date of Patent: July 15, 2008Assignee: Hitachi Chemical Company, Ltd.Inventors: Keiji Sumiya, Nachimuthu Senguttuvan, Hiroyuki Ishibashi
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Patent number: 7344595Abstract: The method for producing single crystals includes drying crystal raw material by removing water, reaction of impurities with a scavenger, preferably a metal halide, and homogenizing the melt. The method is performed with the raw material in a melt vessel with a variable-sized through-going opening, in which drying occurs at 100° C. to 600° C. for at least 20 hours with a geometric conductance value for the through-going opening of 2.00 to 30.00 mm2; the reacting occurs at 600° C. to 1200° C. for at least nine hours with a geometric conductance value of 0.0020 to 0.300 mm2 and the homogenizing occurs at above 1400° C. for at least six hours with a geometric conductance value of 0.25 to 1.1 mm2. Alternatively the geometric conductance value is the same during drying, reacting and homogenizing and takes a value between 0.25 and 1 mm2.Type: GrantFiled: January 24, 2005Date of Patent: March 18, 2008Assignee: Schott AGInventors: Joerg Kandler, Lutz Parthier, Thomas Kaufhold, Gunther Wehrhan, Clemens Kunisch
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Patent number: 7211146Abstract: A crucible for growing III-nitride (e.g., aluminum nitride) single crystals is provided. The crucible includes an elongated wall structure defining an interior crystal growth cavity. Embodiments include a plurality of grains and a wall thickness of at least about 1.5 times the average grain size. In particular embodiments, the crucible includes first and second layers of grains the first layer including grains forming an inside surface thereof and the second layer being superposed with the first layer. The crucible may be fabricated from tungsten-rhenium (W—Re) alloys; rhenium (Re); tantalum monocarbide (TaC); tantalum nitride (Ta2N); hafnium nitride (HfN); a mixture of tungsten and tantalum (W—Ta); tungsten (W); and combinations thereof.Type: GrantFiled: April 12, 2004Date of Patent: May 1, 2007Assignee: Crystal IS, Inc.Inventors: Leo J. Schowalter, Glen A. Slack
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Patent number: 7118789Abstract: A silica glass crucible is manufactured by introducing into a rotating crucible mold bulk silica grain to form a bulky wall including a bottom wall and a side wall. After heating the interior of the mold to begin to fuse the bulk silica grains, an inner silica grain, doped with aluminum, is introduced. The heat at least partially melts the inner silica grain, allowing it to fuse to the wall to form an inner layer. The crucible is cooled, the fused silica grains forming nuclei of crystalline silica within the inner layer.Type: GrantFiled: July 16, 2001Date of Patent: October 10, 2006Assignee: Heraeus Shin-Etsu AmericaInventors: Katsuhiko Kemmochi, Robert O. Mosier, Paul G. Spencer
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Patent number: 6984263Abstract: In a single crystal pulling apparatus for providing a Czochralski crystal growth process, the improvement of a shallow melt crucible (20) to eliminate the necessity supplying a large quantity of feed stock materials that had to be preloaded in a deep crucible to grow a large ingot, comprising a gas tight container a crucible with a deepened periphery (25) to prevent snapping of a shallow melt and reduce turbulent melt convection; source supply means for adding source material to the semiconductor melt; a double barrier (23) to minimize heat transfer between the deepened periphery (25) and the shallow melt in the growth compartment; offset holes (24) in the double barrier (23) to increase melt travel length between the deepened periphery (25) and the shallow growth compartment; and the interface heater/heat sink (22) to control the interface shape and crystal growth rate.Type: GrantFiled: November 1, 2001Date of Patent: January 10, 2006Assignee: Midwest Research InstituteInventors: Tihu Wang, Theodore F. Ciszek
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Publication number: 20040187771Abstract: To provide a silica glass crucible, wherein there are no problems of generating a sinking and buckling when said crucible is used for pulling up silicon single crystal at a high temperature. The silica glass crucible used for pulling up the silicon single crystal, wherein at least an outer surface of a wall part of the crucible is covered with fine grooves having a length of less than 200 &mgr;m, a width of less than 30 &mgr;m and a depth of from more than 3 &mgr;m to less than 30 &mgr;m. Preferably, said fine groves are formed by carrying out a sand-blast treatment and a hydrofluoric acid etching and exist on more than 10% of the outer surface of the crucible, and a sliding frictional coefficient of the outer surface of the crucible to a carbon at 1500 degree C. is more than 0.6.Type: ApplicationFiled: March 17, 2004Publication date: September 30, 2004Applicant: JAPAN SUPER QUARTZ CORPORATIONInventors: Yoshiyuki Tsuji, Toshio Tsujimoto
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Patent number: 6719843Abstract: A crucible for growing III-nitride (e.g., aluminum nitride) single crystals is provided. The crucible includes an elongated wall structure defining an interior crystal growth cavity. The crucible includes a plurality of tungsten grains and a wall thickness of at least about 1.5 times the average tungsten grain size. In particular embodiments, the crucible includes first and second layers of tungsten grains the first layer including grains forming an inside surface thereof and the second layer being superposed with the first layer. The crucible may be machined from a bar, plate, or billet of powder metallurgy tungsten.Type: GrantFiled: September 20, 2002Date of Patent: April 13, 2004Assignee: Crystal Is, Inc.Inventors: Leo J. Schowalter, Glen A. Slack
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Patent number: 6562133Abstract: A crucible having an inner surface is not wetted by a melt which shrinks when it solidifies is provided with indentations in the walls of the crucible to support an ingot grown in it. Supporting the crystal provides a gap between the bottom of the ingot and the inner surface of the bottom of the crucible. The gap allows more uniform heat transfer from the bottom of the crucible than is provided when there is no gap; the gap provides a controllable temperature gradient between the interior and exterior of the crucible. To direct propagation of the growth of a macrocrystal the bottom of the crucible is provided with at least one set of multiple grooves in parallel relationship with each other. Preferably a second set of multiple grooves in parallel relationship with each other intersect the grooves of the first set at an angle chosen depending upon the lattice structure of the macrocrystal to be grown. A macrocrystal grown in a crucible with twin sets of angulated grooves produces single crystals.Type: GrantFiled: July 12, 2001Date of Patent: May 13, 2003Inventor: Carl Francis Swinehart
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Patent number: 6451711Abstract: A system for coating the surface of compound semiconductor wafers includes providing a single-wafer epitaxial production system in a cluster-tool architecture with a loading, storage, and transfer modules, a III-V deposition chamber, and an insulator deposition chamber. The compound semiconductor wafer is placed in the loading and transfer module and the pressure is reduced to less than 5×10−10 Torr, after which the wafer is moved to the III-V growth chamber and layers of compound semiconductor material are epitaxially grown on the surface of the wafer. The single wafer is then moved through the transfer module to the insulator chamber and an insulating cap layer is formed by thermally evaporating molecules, consisting essentially of gallium and oxygen, from an effusion cell using a thermal evaporation source that utilizes a metallic iridium crucible that is manufactured using the electroforming process.Type: GrantFiled: August 4, 2000Date of Patent: September 17, 2002Assignee: Osemi, IncorporatedInventor: Walter David Braddock, IV
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Patent number: 6423136Abstract: A crucible having an inner surface which is not wetted by a melt which shrinks when it solidifies, is provided with indentations in its walls, the indentatons located remote from its rim. The indentations are located beneath a lateral plane through the walls of the crucible, at about two-thirds (66.6%) of the vertical height of the walls, measured from the floor of the crucible, support an ingot grown in it. Supporting the crystal provides a gap between the bottom of the ingot and the inner surface of the bottom of the crucible. The gap allows more uniform heat transfer from the bottom of the crucible than is provided when there is no gap; the gap provides a controllable temperature gradient between the interior and exterior of the crucible. To direct propagation of the growth of a macrocrystal, the bottom of the crucible is provided with at least one set of multiple grooves in parallel relationship with each other.Type: GrantFiled: January 30, 2001Date of Patent: July 23, 2002Inventor: Carl Francis Swinehart
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Patent number: 6364947Abstract: In method for manufacturing a silicon single crystal in accordance with a Czochralski method, during the growth of the silicon single crystal, pulling is performed such that a solid-liquid interface in the crystal, excluding a peripheral 5 mm-width portion, exists within a range of an average vertical position of the solid-liquid interface ±5 mm. There is also disclosed a method for manufacturing a silicon single crystal in accordance with the Czochralski method, wherein during the growth of a silicon single crystal, a furnace temperature is controlled such that a temperature gradient difference &Dgr;G (=Ge−Gc) is not greater than 5° C./cm, where Ge is a temperature gradient (° C./cm) at a peripheral portion of the crystal, and Gc is a temperature gradient (° C./cm) at a central portion of the crystal, both in an in-crystal descending temperature zone between 1420° C. and 1350° C. or between a melting point of silicon and 1400° C.Type: GrantFiled: September 14, 2000Date of Patent: April 2, 2002Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Makoto Iida, Eiichi Iino, Masanori Kimura, Shozo Muraoka, Hideki Yamanaka
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Patent number: 6200385Abstract: A crucible 40 having an inner surface 42 not wetted by a melt which shrinks when it solidifies is provided with indentations 41 in the walls of the crucible to support an ingot grown in it. Supporting the crystal provides a gap between the bottom of the ingot 44 and the inner surface of the bottom of the crucible. The gap allows more uniform heat transfer from the bottom of the crucible than is provided when there is no gap; the gap provides a controllable temperature gradient between the interior and exterior of the crucible. To direct propagation of the growth of a macrocrystal, the bottom of the crucible is provided with at least one set of multiple grooves in parallel relationship with each other. Preferably a second set of multiple grooves in parallel relationship with each other intersect the grooves of the first set at an angle chosen depending upon the lattice structure of the macrocrystal to be grown. A macrocrystal grown in a crucible with twin sets of angulated grooves produces single crystals.Type: GrantFiled: March 20, 2000Date of Patent: March 13, 2001Inventor: Carl Francis Swinehart
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Patent number: 6153011Abstract: Reactive gas is released through a crystal source material or melt to react with impurities and carry the impurities away as gaseous products or as precipitates or in light or heavy form. The gaseous products are removed by vacuum and the heavy products fall to the bottom of the melt. Light products rise to the top of the melt. After purifying, dopants are added to the melt. The melt moves away from the heater and the crystal is formed. Subsequent heating zones re-melt and refine the crystal, and a dopant is added in a final heating zone. The crystal is divided, and divided portions of the crystal are re-heated for heat treating and annealing.Type: GrantFiled: February 16, 2000Date of Patent: November 28, 2000Assignee: Optoscint, Inc.Inventor: Kiril A. Pandelisev
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Patent number: 5993545Abstract: A sintered rhenium crucible, highly suitable for growing single crystals from refractory metal oxides, for example by the Czochralski technique, is formed of fine rhenium powder, by sintering. A compact is formed by cold isostatic pressing and thereafter the compact is sintered at 500-2800.degree. C. to obtain a sintered crucible. Product density is limited to 88-95% of theroretical in order to maximize creep resistance.Type: GrantFiled: January 9, 1998Date of Patent: November 30, 1999Assignee: W.C. Heraeus GmbH & Co. KGInventors: David Francis Lupton, Jorg Schielke, Manfred Weigelt, Klaus Petermann, Eric Mix, Livio Fornasiero
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Patent number: 5427057Abstract: A self-clamping holder capable of holding a polysilicon rod using the weight of the polysilicon rod is disclosed. The holder includes a generally cup-shaped adapter having an open end facing downward, and at least three clamp jaws rotatably mounted on the adapter adjacent to the open end and circumferentially spaced at equal angular intervals for clamping or gripping an end of the polysilicon rod received in the adapter. The clamp jaws have arcuate cam surfaces disposed interiorly of the adapter and profiled such that a radius of curvature of the cam surfaces gradually increases as the clamp jaws turn in a downward direction of the adapter. With this construction, the polysilicon rod is firmly gripped by the clamp jaws against detachment from the holder. The clamp jaws produces a clamping force acting on the peripheral surface of the polysilicon rod and distributed uniformly in the circumferential direction of the polysilicon rod.Type: GrantFiled: July 29, 1994Date of Patent: June 27, 1995Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Michiaki Hattori, Keiichi Nakazawa
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Patent number: 5375557Abstract: An apparatus (10) and method are provided for directly viewing, through a viewport assembly (26), the process for forming a layer of mercury cadmium telluride of a predetermined composition on a surface of a wafer (not shown). According to the invention, a molten melt (20) comprising mercury, cadmium and tellurium is provided in a vertically oriented crystal growth chamber (14), which, in turn, is housed in a reactor tube (12). A wafer (not shown) is contacted with the crystal growth melt while cooling the melt below its liquidus temperature at a predetermined rate sufficient to cause a crystal growth layer of mercury cadmium telluride to form on the wafer (not shown). Viewports (26, 48) located approximately radially adjacent to the melt (22) provide direct see through capability to visually monitor the crystal growth process.Type: GrantFiled: October 28, 1993Date of Patent: December 27, 1994Assignee: Texas Instruments IncorporatedInventor: Jeffrey M. Anderson
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Patent number: 5308800Abstract: Apparatus and method for fabricating textured pseudo-single crystal bulk superconducting materials, featuring introduction of a pressure gradient and/or of a magnetic field for enhancement of known melt-texturing directional solidification techniques using a steep temperature gradient furnace for increasing temperatures at which superconductive properties can be maintained in superconducting materials. The strengths of the temperature gradient, pressure gradient and/or magnetic field can be optimally varied, resulting in formation of superconducting material exhibiting superconductive properties at higher temperatures than previously achievable.Type: GrantFiled: March 23, 1992Date of Patent: May 3, 1994Assignee: The United States of America as represented by the Secretary of the NavyInventors: John P. Wehrle, Barbara F. Howell, James G. Morris, III