Patents Examined by Felisa Hiteshew
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Patent number: 7214412Abstract: When exposing a sample to be oxidized 10 to ozone gas so as to form an oxide film on the surface of the sample, an area to be oxidized is heated locally. Local heating is carried out with a light source 23 for irradiating infrared light the area to be oxidized of the sample on the susceptor 21, and heating means for heating the susceptor. Moreover, when exposing the sample to be oxidized to ozone gas, ozone gas is supplied to the sample while heating the sample under a given pressure. Said pressure is adjusted at 100–44,000 Pa, for example. The flow rate of ozone gas is adjusted, preferably, so that flow of ozone gas in a furnace 20 forms laminar flow. Moreover, it is desirable to provide a light source for emitting ultraviolet light. The light source for emitting ultraviolet light is arranged to irradiate the upstream side of the susceptor 21, for example.Type: GrantFiled: October 31, 2002Date of Patent: May 8, 2007Assignees: Kabushiki Kaisha Meidensha, National Institute of Advanced Industrial ScienceInventors: Tetsuya Nishiguchi, Hidehiko Nonaka, Shingo Ichimura
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Patent number: 7214268Abstract: The present invention is a method of producing a P(phosphorus)-doped silicon single crystal by Czochralski method, wherein, at least, a growth of the single crystal is performed so that an Al (aluminum) concentration is 2×1012 atoms/cc or more. Thereby, there can be provided a method of easily and inexpensively producing a P(phosphorus)-doped silicon single crystal of defect-free region having an excellent capability of electrical characteristics to be high breakdown voltage, which contains neither, for example, V region, OSF region, nor large dislocation cluster (LSEPD, LFPD) region.Type: GrantFiled: December 25, 2003Date of Patent: May 8, 2007Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Masahiro Sakurada, Izumi Fusegawa
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Patent number: 7211141Abstract: The present invention is a method for producing a wafer comprising, at least, a BMD forming step of subjecting a silicon single crystal in a state of an ingot to heat treatment thereby to form bulk micro defects (BMDs) inside, and a wafer processing step of processing the ingot in which the bulk micro defects (BMDs) was formed into wafers. Thereby, there can be provided a method for producing a wafer, wherein heat treatment for providing IG capability in production of wafer can be shortened and wafers with high IG capability can be produced in large quantity. Also, the present invention can further comprise a wafer heat-treating step of subjecting the processed wafer to heat treatment, or an epitaxial growth step of forming an epitaxial layer on the wafer. Thereby, there is improved productivity of annealed wafers or epitaxial wafers that are excellent in gettering capability.Type: GrantFiled: August 4, 2004Date of Patent: May 1, 2007Assignee: Shin-Etsu Handotai Co., Ltd.Inventor: Takeshi Kobayashi
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Method of manufacturing silicon single crystal and silicon single crystal manufactured by the method
Patent number: 7208042Abstract: A silicon single crystal ingot is pulled at a pull rate so that the interior of the ingot results in a perfect region in which agglomerates of interstitial silicon-type point defects and agglomerates of vacancy-type point defects are absent, while rotating a quartz crucible for storing a silicon melt at a predetermined rotation speed and rotating the ingot pulled from the silicon melt in the opposite direction to the rotation of the quartz crucible at a predetermined rotation speed. An average rotation speed CRTAV of the quartz crucible during the pulling of a top ingot portion is set to be faster than an average rotation speed CRTAV of the quartz crucible during the pulling of a bottom ingot portion of the silicon single crystal ingot.Type: GrantFiled: January 30, 2004Date of Patent: April 24, 2007Assignee: Sumitomo Mitsubishi Silicon CorporationInventors: Kazuhiro Harada, Yoji Suzuki, Hidenobu Abe -
Patent number: 7204881Abstract: There are disclosed a silicon wafer for epitaxial growth wherein the wafer is produced by slicing a silicon single crystal grown with doping nitrogen according to the Czochralski method (CZ method) in the region where at least the center of the wafer becomes V region in which the void type defects are generated, and wherein the number of defects having an opening size of 20 nm or less among the void type defects appearing on the surface of the wafer is 0.02/cm2 or less, and an epitalial wafer wherein an epitaxial layer is formed on the silicon wafer for epitaxial growth. Thereby, there can be produced an epitaxial wafer having a high gettering capability wherein very few SF exist in the epitaxial layer easily at high productivity and at low cost.Type: GrantFiled: July 8, 2003Date of Patent: April 17, 2007Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Ryoji Hoshi, Susumu Sonokawa
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Patent number: 7201799Abstract: An automated, non-invasive method for classifying, detecting, and counting micropipes contained within silicon wafers, and generally any assortment of transparent wafers. Classifying, detecting, and counting micropipes takes place through the use of a data processing algorithm that incorporates information regarding: defect size; pit signature; area of pit signature when comparing a topography, specular, or scatter images; and detecting a tail within the standard pit signature. The method of the present invention teaches the development of a topography defect map, specular defect map, and scatter defect map for a complete analysis of the surface of a particular transparent wafer. Conventional detection, classification, and counting of micropipes involve characterization of micropipes in a manual fashion and rely upon an extremely invasive form of sample preparation.Type: GrantFiled: November 24, 2004Date of Patent: April 10, 2007Assignee: KLA-Tencor Technologies CorporationInventor: Vamsi Velidandla
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Patent number: 7201801Abstract: The present invention provides a heater for manufacturing a crystal by the Czochralski method comprising at least terminal portions supplied with current and a heat generating portion by resistance heating, and being arranged so as to surround a crucible containing a raw material melt, wherein the heater has a uniform heat generation distribution to the raw material melt after deformation while in use during crystal manufacture. It is thus possible to prevent hindrance of monocrystallization and unstable crystal quality caused by ununiform temperature in the raw material melt due to deformation of the shape of the heater's heat generating portion while in use during crystal manufacture.Type: GrantFiled: September 8, 2003Date of Patent: April 10, 2007Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Susumu Sonokawa, Ryoji Hoshi, Wataru Sato, Tomohiko Ohta
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Patent number: 7201800Abstract: A process for imparting controlled oxygen precipitation behavior to a single crystal silicon wafer. Specifically, prior to formation of the oxygen precipitates, the wafer bulk comprises dopant stabilized oxygen precipitate nucleation centers. The dopant is selected from a group consisting of nitrogen and carbon, and the concentration of the dopant is sufficient to allow the oxygen precipitate nucleation centers to withstand thermal processing, such as an epitaxial deposition process, while maintaining the ability to dissolve any grown-in nucleation centers.Type: GrantFiled: October 12, 2004Date of Patent: April 10, 2007Assignee: MEMC Electronic Materials, Inc.Inventors: Luciano Mule'Stagno, Jeffrey L. Libbert, Richard J. Phillips, Milind Kulkarni, Mohsen Banan, Stephen J. Brunkhorst
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Patent number: 7198673Abstract: A method of making below 250-nm UV light transmitting optical fluoride lithography crystals includes applying heat along a shortest path of conduction of a selected optical fluoride crystal, heating the optical fluoride crystal to an annealing temperature, holding the temperature of the optical fluoride crystal at the annealing temperature, and gradually cooling the optical fluoride crystal to provide a low-birefringence optical fluoride crystal for transmitting below 250-nm UV light.Type: GrantFiled: February 16, 2005Date of Patent: April 3, 2007Assignee: Corning IncorporatedInventors: John H. Brennan, Michael W. Price, Juergen Tinz, Liming Wang
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Patent number: 7198670Abstract: A polarization inverting region is formed by using a board comprising a single crystal of lithium tatalate of a stoichiometric composition or near to the stoichiometric composition and applying a direct current electric field having an electric field intensity equal to or lower than 5 [kV/mm] for 1 [second] or longer. A periodically poled region can be formed without needing a complicated constitution for applying a pulse voltage or a complicated constitution for applying a strong electric field.Type: GrantFiled: January 20, 2005Date of Patent: April 3, 2007Assignee: Shimadzu CorporationInventors: Katuhiko Tokuda, Kazutomo Kadokura
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Patent number: 7195669Abstract: A silicon single crystal rod (24) is pulled from a silicon melt (13) made molten by a heater (17), and a change in diameter of the silicon single crystal rod every predetermined time is fed back to a pulling speed of the silicon single crystal rod and a temperature of the heater, thereby controlling a diameter of the silicon single crystal rod. A PID control in which a PID constant is changed on a plurality of stages is applied to a method which controls the pulling speed of the silicon single crystal rod so that the silicon single crystal rod has a target diameter and a method which controls a heater temperature so that the silicon single crystal rod has the target temperature. A set pulling speed for the silicon single crystal rod is set so that V/G becomes constant, and an actual pulling speed is accurately controlled so as to match with the set pulling speed, thereby suppressing a fluctuation in diameter of the single crystal rod.Type: GrantFiled: July 7, 2003Date of Patent: March 27, 2007Assignee: Sumitomo Mitsubishi Silicon CorporationInventors: Daisuke Wakabayashi, Masao Saito, Satoshi Sato, Jun Furukawa, Kounosuke Kitamura
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Patent number: 7195671Abstract: An apparatus for growing crystals includes a sealed chamber having a crucible assembly and a seed holder disposed therein. The crucible assembly is adapted to contain a melt therein and the seed holder is selectively positionable within the chamber from a first position relative to the crucible assembly to at least one subsequent position within the crucible assembly. A heater is configured and dimensioned to heat the melt disposed within the crucible assembly and an insulator is included for insulating the heater and the crucible. An actuator rotates at least one of the crucible assembly and the seed holder relative to the other and a support ring suspends the crucible assembly within the sealed chamber. A ceramic thermal shield is disposed atop the support ring and regulates the heat loss from the crucible assembly to an upper portion of the chamber.Type: GrantFiled: September 24, 2004Date of Patent: March 27, 2007Assignee: Siemens Medical Solutions USA, Inc.Inventors: Olexy V. Radkevich, Dennis Persyk, Volodimir Protsenko
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Patent number: 7195668Abstract: A crucible for the growth of single crystals by the Czochralski method which can enhance the productivity, yield and quality of crystal and a single crystal growing method, wherein the crucible has an inner bottom surface, the profile of which has at least one raised portion symmetrical about the rotary axis of the crucible wherein the periphery of the raised portion is positioned at a distance of from 0.4 to 1.2 times the radius of crystal to be grown from the rotary axis and the height of the raised portion is generally not smaller than 7% and greater than 100% of the radius of crystal to be grown.Type: GrantFiled: December 22, 2004Date of Patent: March 27, 2007Assignee: Siltronic AGInventors: Yutaka Kishida, Teruyuki Tamaki
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Patent number: 7192481Abstract: A radiation detector made from a compound, or alloy, comprising CdxZn1?xTe (0=x=1), Pb in a concentration between 10 and 10,000 atomic parts per billion and at least one element selected from the group consisting of (i) Cl and (ii) elements in column III of the periodic table in a concentration between 10 and 10,000 atomic parts per billion. The radiation detector exhibits full electrical compensation, high-resistivity, full depletion under an applied electrical bias and excellent charge transport.Type: GrantFiled: June 10, 2003Date of Patent: March 20, 2007Assignee: II-VI IncorporatedInventors: Csaba Szeles, Kelvin G. Lynn
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Patent number: 7192482Abstract: A silicon carbide seeded sublimation growth system and associated method are disclosed. The system includes a crucible, a silicon carbide source composition in the crucible, a seed holder in the crucible, a silicon carbide seed crystal on the seed holder, means for creating a major thermal gradient in the crucible that defines a major growth direction between the source composition and the seed crystal for encouraging vapor transport between the source composition and the seed crystal, and the seed crystal being positioned on the seed holder with the macroscopic growth surface of the seed crystal forming an angle of between about 70° and 89.5° degrees relative to the major thermal gradient and the major growth direction and with the crystallographic orientation of the seed crystal having the c-axis of the crystal forming an angle with the major thermal gradient of between about 0° and 2°.Type: GrantFiled: August 10, 2004Date of Patent: March 20, 2007Assignee: Cree, Inc.Inventors: Stephan Mueller, Adrian Powell, Valeri F. Tsvetkov
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Patent number: 7192480Abstract: A method for fabricating ion exchange waveguides, such as lithium niobate or lithium tantalate waveguides in optical modulators and other optical waveguide devices, utilizes pressurized annealing to further diffuse and limit exchange of the ions and includes ion exchanging the crystalline substrate with a source of ions and annealing the substrate by pressurizing a gas atmosphere containing the lithium niobate or lithium tantalate substrate above normal atmospheric pressure, heating the substrate to a temperature ranging from about 150 degrees Celsius to about 1000 degrees Celsius, maintaining pressure and temperature to effect greater ion diffusion and limit exchange, and cooling the structure to an ambient temperature at an appropriate ramp down rate. In another aspect of the invention a powder of the same chemical composition as the crystalline substrate is introduced into the anneal process chamber to limit the crystalline substrate from outgassing alkaline earth metal oxide during the anneal period.Type: GrantFiled: August 16, 2004Date of Patent: March 20, 2007Assignee: California Institute of TechnologyInventor: Lee J. Burrows
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Patent number: 7182809Abstract: A single crystal silicon, ingot or wafer form, which contains an axially symmetric region in which vacancies are the predominant intrinsic point defect, is substantially free of oxidation induced stacking faults and is nitrogen doped to stabilize oxygen precipitation nuclei therein, and a process for the preparation thereof.Type: GrantFiled: August 30, 2001Date of Patent: February 27, 2007Assignee: MEMC Electronic Materials, Inc.Inventors: Hiroyo Haga, Takaaki Aoshima, Mohsen Banan
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Patent number: 7179331Abstract: The invention presented here relates to a crystal growing equipment. It is equipped in general with a resistance heater for heating a melt (13) as well as with field coils, which generate alternating magnetic field in a crucible, with which flows can be induced in the melt (13). The invention is so designed that the resistance heaters are also devised to function as the field coils, that is, they are built of a hollow cylindrical body (1), in which, by means of a surrounding slit (2) which winds around it, a spiral-shaped single layer current path is formed. This has the advantage that the current needed for the electrical heating in the equipment is also used for the generation of the magnetic field. Thus, neither separate field coils nor a separate current supply is necessary. Further, the resistance heater, which serves as the field coil arranged as a coil array, is high temperature resistant and surrounds the immediate hot core zone of the equipment and thus the region of the melt.Type: GrantFiled: August 19, 2004Date of Patent: February 20, 2007Assignee: Crystal Growing Systems GmbHInventors: Andreas Mühe, Burkhard Altekrüger, Axel Vonhoff
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Patent number: 7175708Abstract: Methods and apparatus are provided for the removal and purification of the water and salt by-products from spent BHP emitted from a lasing process. The apparatus comprises a liquid processing system that freezes the water and salt by-products into a slurry, and then separates out the water (as ice) and salt components by filtering in a centrifuge. In order to remove as much residual BHP from the wet mixed ice-salt component as possible, a heat source is used to partially melt ice crystals, thereby generating an aqueous rinsing liquid on the surface of the wet mixed ice-salt crystals. The applied centrifugal force causes a continual displacement of the liquid film wetting the surface, so that it becomes progressively diluted. As such, the purification of the mixture of ice and salt crystals is implemented with an aqueous (water) rinse that is unaffected by the sub-freezing temperatures within the centrifuge.Type: GrantFiled: July 28, 2005Date of Patent: February 13, 2007Assignee: The Boeing CompanyInventors: David Stelman, Steven M. Klee
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Patent number: 7175706Abstract: There is provided a process of producing a multicrystalline silicon substrate having excellent characteristics as a solar cell substrate. A multicrystalline silicon ingot made by directional solidification 10 is cut such that a normal line of a principal surface 14 of a multicrystalline silicon substrate 13 is substantially perpendicular to a longitudinal direction of crystal grains 11 of the multicrystalline silicon ingot made by directional solidification 10.Type: GrantFiled: February 21, 2003Date of Patent: February 13, 2007Assignee: Canon Kabushiki KaishaInventors: Masaki Mizutani, Shunichi Ishihara, Katsumi Nakagawa, Hiroshi Sato, Takehito Yoshino, Shoji Nishida, Noritaka Ukiyo, Masaaki Iwane, Yukiko Iwasaki