Having Pulling During Growth (e.g., Czochralski Method, Zone Drawing) Patents (Class 117/13)
  • Patent number: 7258739
    Abstract: Firstly, a silicon ingot in which boron and germanium were doped is sliced to prepare a silicon wafer and then the wafer is thermally processed by oxidation to form the thermal oxidation film on the surface layer portion of the wafer. Thereby, the concentration of germanium is enhanced in the vicinity of the interface with the thermal oxidation film of the wafer. Then, the thermal oxidation film is removed from the surface layer portion of the wafer. Further, an epitaxial layer consisting of a silicon single crystal in which a lower concentration of boron than the concentration of boron in the wafer was doped is grown on the shallow surface layer portion of the wafer by an epitaxial growth method. According to the present invention, the doping amount of germanium is reduced and the generation of misfit dislocations is suppressed.
    Type: Grant
    Filed: February 4, 2005
    Date of Patent: August 21, 2007
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Toshiaki Ono, Masataka Hourai
  • Patent number: 7255740
    Abstract: A method is described for making low-stress single crystals with a hexagonal crystal structure, which has a crystallographic c-axis perpendicular to a [0001] surface. A single crystal maintained at a temperature under the melting point of the crystal raw material is dipped in a melt of the crystal raw material, whereby a solid-liquid phase boundary is formed. The crystal is subsequently drawn with an upwardly directed drawing motion e.g. by the Czochralski method. The method is characterized by drawing the crystal along the c-axis so that a temperature gradient of at least 30 K/cm is present in the crystal within a centimeter of the solid-liquid phase boundary and by subsequently performing a tempering treatment on the resulting single crystal. The method is especially suitable for corundum crystals, such as sapphire, which are used as substrates for semiconductor components, such as LEDs.
    Type: Grant
    Filed: February 17, 2004
    Date of Patent: August 14, 2007
    Assignee: Schott AG
    Inventors: Dirk Sprenger, Burkhard Speit, Markus Schweizer
  • Publication number: 20070169685
    Abstract: Methods and apparatuses are provided for casting silicon for photovoltaic cells and other applications. With such methods and apparatuses, a cast body of geometrically ordered multi-crystalline silicon may be formed that is free or substantially free of radially-distributed impurities and defects and having at least two dimensions that are each at least about 10 cm is provided.
    Type: Application
    Filed: January 18, 2007
    Publication date: July 26, 2007
    Applicant: BP Corporation North America Inc.
    Inventor: Nathan G. Stoddard
  • Publication number: 20070169684
    Abstract: Methods and apparatuses are provided for casting silicon for photovoltaic cells and other applications. With such methods and apparatuses, a cast body of monocrystalline silicon may be formed that is free of, or substantially free of, radially-distributed impurities and defects and having at least two dimensions that are each at least about 35 cm is provided.
    Type: Application
    Filed: January 18, 2007
    Publication date: July 26, 2007
    Applicant: BP Corporation North America Inc.
    Inventor: Nathan G. Stoddard
  • Publication number: 20070163485
    Abstract: The disclosure relates to an apparatus and a method for producing a single crystal of semiconductor material. The apparatus comprises a chamber and a crucible which is arranged in the chamber and is enclosed by a crucible heater, a radiation shield for shielding a growing single crystal and thermal insulation between the crucible heater and an inner wall of the chamber. The apparatus may include a resilient seal which seals a gap between the inner wall and the thermal insulation and forms an obstacle for the transport of gaseous iron carbonyls to the single crystal. The disclosure also relates to a method for producing a single crystal of semiconductor material by using the apparatus, the single crystal which is produced and a semiconductor wafer cut therefrom.
    Type: Application
    Filed: January 18, 2007
    Publication date: July 19, 2007
    Inventors: Laszlo Fabry, Gunter Strebel, Hans Oelkrug
  • Patent number: 7244306
    Abstract: A single crystal ingot is cut to an axial direction so as to including the central axis, a sample for measurement including regions [V], [Pv], [Pi] and [I] is prepared, and a first sample and second sample are prepared by dividing the sample into two so as to be symmetrical against the central axis. A first transition metal is metal-stained on the surface of the first sample and a second transition metal different from the first transition metal is metal-stained on the surface of the second sample. The first and second samples stained with the metals are thermally treated and the first and second transition metals are diffused into the inside of the samples. Recombination lifetimes in the whole of the first and second samples are respectively measured, and the vertical measurement of the first sample is overlapped on the vertical measurement of the second sample.
    Type: Grant
    Filed: October 17, 2003
    Date of Patent: July 17, 2007
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Kazunari Kurita, Jun Furukawa
  • Publication number: 20070151505
    Abstract: In a method for producing a high quality silicon single crystal by the Czochralski method, a lower portion of a solid-liquid interface of a single crystal growth is divided into a central part and a circumferential part, and the temperature gradient of the central part and the temperature gradient of the circumferential part are separately controlled. When a silicon melt located at a lower portion of a solid-liquid interface of a single crystal growth is divided into a central part melt and a circumferential part melt, the method controls the temperature gradient of the central part melt by directly controlling the temperature distribution of a melt and indirectly controls the temperature gradient of the circumferential part melt by controlling the temperature gradient of the single crystal, thereby effectively controlling the overall temperature distribution of the melt, thus producing a high quality single crystal ingot free of defects with a high growth velocity.
    Type: Application
    Filed: December 21, 2006
    Publication date: July 5, 2007
    Inventor: Hyon-Jong Cho
  • Patent number: 7235133
    Abstract: By utilizing a crystal pulling apparatus for producing a single crystal according to the Czochralski method comprising at least a crucible to be charged with a raw material, a heater surrounding the crucible, and subsidiary heating means provided below the crucible, a single crystal is pulled or the raw material is additionally introduced with heating by the heater surrounding the crucible and the subsidiary heating means when the amount of the raw material melt in the crucible becomes a limited amount. Thus, there is provided a method for growing a single crystal at a high yield while preventing solidification of melt raw material decreased to a limited amount without affecting crystal quality, durability of crucible or the like even when a crucible having a large diameter is used.
    Type: Grant
    Filed: February 16, 2001
    Date of Patent: June 26, 2007
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventor: Masanori Kimura
  • Patent number: 7235863
    Abstract: A process for producing a single-crystal silicon wafer, comprises the following steps: producing a layer on the front surface of the silicon wafer by epitaxial deposition or production of a layer whose electrical resistance differs from the electrical resistance of the remainder of the silicon wafer on the front surface of the silicon wafer, or production of an external getter layer on the back surface of the silicon wafer, and heat treating the silicon wafer at a temperature which is selected to be such that an inequality (1) [ O ? ? i ] < [ O ? ? i ] eq ? ( T ) ? exp ? ? 2 ? ? SiO ? 2 ? ? r ? ? k ? ? T is satisfied, where [Oi] is an oxygen concentration in the silicon wafer, [Oi]eq(T) is a limit solubility of oxygen in silicon at a temperature T, ?SiO2 is the surface energy of silicon dioxide, ? is a volume of a precipitated oxygen atom, r is a mean COP radius and k the Boltzmann constant, with the silicon wafer, during the heat treatment, at least pa
    Type: Grant
    Filed: July 16, 2004
    Date of Patent: June 26, 2007
    Assignee: Siltronic AG
    Inventors: Christoph Seuring, Robert Hölzl, Reinhold Wahlich, Wilfried Von Ammon
  • Patent number: 7235132
    Abstract: In order to pull semiconductor single crystals by the Czochralski method, quartz glass crucibles are used which require support crucibles having high temperature capabilities. Such support crucibles may be made of various materials, in which case graphite materials, carbon fiber-reinforced carbon (CFC), combinations thereof or carbon materials coated with silicon carbide (SiC) are used. The working life of a CFC support crucible can be extended by a partial thickening of the support crucible walls affected by corrosion processes.
    Type: Grant
    Filed: May 12, 2004
    Date of Patent: June 26, 2007
    Assignee: SGL Carbon AG
    Inventor: Dieter Kompalik
  • Patent number: 7235128
    Abstract: A process for producing a single-crystal semiconductor and an apparatus therefor. A single-crystal semiconductor of large diameter and large weight can be lifted with the use of existing equipment not having any substantial change thereto while not influencing the oxygen concentration of single-crystal semiconductor and the temperature of melt and while not unduly raising the temperature of seed crystal. In particular, the relationship (L1, L2, L3) between the allowable temperature difference (?T) and the diameter (D) of seed crystal (14) is preset so that the temperature difference between the seed crystal (14) at the time the seed crystal (14) is immersed in the melt and the melt (5) falls within the allowable temperature difference (?T) at which dislocations are not introduced into the seed crystal (14). In accordance with the relationship (L1, L2, L3), the allowable temperature difference (?T) corresponding to the diameter (D) of seed crystal (14) to be immersed in the melt is determined.
    Type: Grant
    Filed: December 6, 2004
    Date of Patent: June 26, 2007
    Assignee: Komatsu Denshi Kinzoku Kabushiki Kaisha
    Inventors: Susumu Maeda, Hiroshi Inagaki, Shigeki Kawashima, Shoei Kurosaka, Kozo Nakamura
  • Patent number: 7232484
    Abstract: Semiconductor materials such as silicon particles are doped by mixing the semiconductor material with a solution having a dopan and a solvent. The solvent is removed from the wetted surface of the particles of the semiconductor material, thereby yielding particles that are substantially free from the solvent and are uniformly coated with the dopant.
    Type: Grant
    Filed: November 24, 2004
    Date of Patent: June 19, 2007
    Assignee: Evergreen Solar Inc.
    Inventors: Mary C. Cretella, Richard L. Wallace, Jr.
  • Patent number: 7229494
    Abstract: A method for producing a compound semiconductor single crystal by a liquid encapsulated Czochralski method, including containing a semiconductor raw material and an encapsulating material in a raw material melt-containing portion having a first crucible having a bottom and a cylindrical shape and a second crucible disposed within the first crucible and having a communication hole communicating with the first crucible in a bottom portion thereof; melting the raw material by heating the raw material melt-containing portion; and growing a crystal by making a seed crystal contact with a surface of the raw material melt in a state covered with the encapsulating material and by pulling up the seed crystal. A heater temperature is controlled so that a diameter of a growing crystal becomes approximately equal to an inner diameter of the second crucible, and the crystal is grown by maintaining a surface of the growing crystal in a state covered with the encapsulating material until termination of crystal growth.
    Type: Grant
    Filed: December 17, 2002
    Date of Patent: June 12, 2007
    Assignee: Nippon Mining & Metals Co., Ltd.
    Inventors: Toshiaki Asahi, Kenji Sato, Atsutoshi Arakawa
  • Patent number: 7229495
    Abstract: A method for growing a silicon single crystal ingot by a Czochralski method, which is capable of providing silicon wafers having very uniform in-plane quality and which results in improvement of semiconductor device yield. A method is provided for producing a silicon single crystal ingot by a Czochralski method, wherein when convection distribution of a silicon melt is divided into a core cell and an outer cell, the silicon single crystal ingot is grown under the condition that the maximal horizontal direction width of the core cell is 30 to 60% of a surface radius of the silicon melt. In one embodiment the silicon single crystal ingot is grown under the condition that the maximal vertical direction depth of the core cell is equal to or more than 50% of the maximal depth of the silicon melt.
    Type: Grant
    Filed: December 19, 2003
    Date of Patent: June 12, 2007
    Assignee: Siltron Inc.
    Inventors: Hyon-Jong Cho, Cheol-Woo Lee, Hong-Woo Lee, Jin Soo Cheong, Sunmi Kim
  • Patent number: 7229496
    Abstract: A thermal processing operation is performed for a silicon wafer W (silicon single-crystal layer) in an atmosphere gas which is formed by a hydrogen gas or an inert gas or a mixture gas of these gases at a temperature in a range of 600° C. to 950° C. (here, the temperature should not be greater than 950° C.). By doing this, a quality of a surface of the silicon single-crystal layer is improved.
    Type: Grant
    Filed: March 5, 2003
    Date of Patent: June 12, 2007
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Takashi Shibayama, Yoshio Murakami, Takayuki Shingyoji
  • Patent number: 7226506
    Abstract: A method for eliminating slip dislocations in producing single crystal silicon, a seed crystal capable of eliminating the slip dislocations, a single crystal silicon ingot from which the slip dislocations have been eliminated and a single crystal silicon wafer, are disclosed. Single crystal silicon is produced by dipping a seed crystal in a melt and pulling the seed crystal up along the axis of the seed crystal, using a single crystal (1) in which the <110> crystal orientation (10) is inclined at a predetermined angle ? with respect to the axial direction (9) so that the edge direction (8) of the {111} crystal plane is inclined with respect to the axial direction (9). When single crystal silicon is grown while pulling up a seed crystal by the CZ method, a single crystal silicon ingot of a large diameter and a heavy weight can be pulled up by eliminating slip dislocations from the thick crystal.
    Type: Grant
    Filed: April 17, 2003
    Date of Patent: June 5, 2007
    Assignee: Sumco Techxiv Corporation
    Inventors: Tetsuhiro Iida, Yutaka Shiraishi, Ryota Suewaka, Junsuke Tomioka
  • Patent number: 7226507
    Abstract: The present invention is a method for producing a single crystal of which a whole plane in a radial direction is a defect-free region with pulling the single crystal from a raw material melt in a chamber by Czochralski method, wherein a pulling condition is changed in a direction of the crystal growth axis during pulling the single crystal so that a margin of a pulling rate is always a predetermined value or more that the single crystal of which the whole plane in a radial direction is a defect-free region can be pulled. Thereby, there can be provided a method for producing a single crystal in which when a single crystal is produced by CZ method, the single crystal of which a whole plane in a radial direction is a defect-free region entirely in a direction of the crystal growth axis can be produced with stability.
    Type: Grant
    Filed: May 27, 2004
    Date of Patent: June 5, 2007
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Nobuaki Mitamura, Tomohiko Ohta, Izumi Fusegawa, Masahiro Sakurada, Atsushi Ozaki
  • Patent number: 7226505
    Abstract: A method for eliminating defects in single crystal silicon, which comprises subjecting single crystal silicon prepared by the CZ method to an oxidation treatment and then to an ultra high temperature heat treatment at a temperature of at least 1300° C., or comprises subjecting single crystal silicon which is prepared by the CZ method and is not subjected to an oxidation treatment (a bare wafer) to an ultra high temperature heat treatment in an oxygen atmosphere and at a temperature of higher than 1200° C. and lower than 1310° C. The method allows the elimination of void defects present in single crystal silicon with reliability.
    Type: Grant
    Filed: December 25, 2002
    Date of Patent: June 5, 2007
    Assignee: Sumco Techxiv Corporation
    Inventors: Masahiko Ando, Masaru Yuyama, Shiro Yoshino
  • Patent number: 7223303
    Abstract: A cleaning method cleans silicon for semiconductor materials using pure water treated by a reverse osmosis treatment and by ion exchange treatment and reduces the aluminum and iron remaining on the silicon surface.
    Type: Grant
    Filed: August 26, 2004
    Date of Patent: May 29, 2007
    Assignees: Mitsubishi Materials Corporation, Mitsubishi Polycrystalline Silicon America Corporation
    Inventor: Hirotake Ohta
  • Patent number: 7220308
    Abstract: To suppress a fluctuation in resistivity around a target value to thereby stably manufacture high resistivity silicon single crystals having almost the same resistivity values in a manufacturing method wherein a silicon raw material is molten to manufacture a high resistivity silicon single crystal in the range of from 100 to 2000 ? cm with a CZ method. In a case where poly-silicon produced with a Siemens method using trichlorosilane as raw material is used as the silicon raw material, an impurity concentration in the silicon raw material is selected so as to be controlled in the range of from ?5 to 50 ppta method in terms of (a donor concentration—an acceptor concentration) and the selected poly-silicon is used. In a case of a MCZ method, the poly-silicon is selected in the range of from ?25 to 20 ppta and the selected poly-silicon is used. Instead of the raw material, poly-silicon produced with a Siemens method using monosilane as raw material is used.
    Type: Grant
    Filed: April 21, 2004
    Date of Patent: May 22, 2007
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Nobumitsu Takase, Hideshi Nishikawa, Makoto Ito, Koujl Sueoka, Shinsuke Sadamitsu
  • Patent number: 7217320
    Abstract: The present invention relates to a process for preparing a single crystal silicon ingot, as well as to the ingot or wafer resulting therefrom. The process comprises controlling (i) a growth velocity, v, (ii) an average axial temperature gradient, G0, and (iii) a cooling rate of the crystal from solidification to about 750° C., in order to cause the formation of a segment having a first axially symmetric region extending radially inward from the lateral surface of the ingot wherein silicon self-interstitials are the predominant intrinsic point defect, and a second axially symmetric region extending radially inward from the first and toward the central axis of the ingot.
    Type: Grant
    Filed: December 7, 2004
    Date of Patent: May 15, 2007
    Assignee: MEMC Electronics Materials, Inc.
    Inventors: Chang Bum Kim, Steven L. Kimbel, Jeffrey L. Libbert, Mohsen Banan
  • Patent number: 7214267
    Abstract: A silicon single crystal and a method for growing a silicon single crystal are provided. A p-type silicon single crystal is grown with a uniform resistivity value in a pulling direction. Pulling is conducted by the Czochralski method from molten silicon obtained by adding phosphorus to an initial melt in an amount equivalent to 25˜35% of an absolute concentration (atoms/cc) of boron contained in the melt.
    Type: Grant
    Filed: May 12, 2004
    Date of Patent: May 8, 2007
    Assignee: Sumitomo Mitsubishi Silicon
    Inventor: Koji Kato
  • Patent number: 7214268
    Abstract: 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: Grant
    Filed: December 25, 2003
    Date of Patent: May 8, 2007
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Masahiro Sakurada, Izumi Fusegawa
  • Patent number: 7211141
    Abstract: 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: Grant
    Filed: August 4, 2004
    Date of Patent: May 1, 2007
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventor: Takeshi Kobayashi
  • Patent number: 7211142
    Abstract: A CdTe single crystal, wherein chlorine concentration in the crystal is between 0.1 and 5.0 ppmwt and resistivity at room temperature is not less than 1.0×109 ?·cm is obtained by growing the crystal according to one of a vertical gradient freezing method, a horizontal gradient freezing method, a vertical Bridgman method, a horizontal Bridgman method, and a liquid encapsulated Czochralski method by using a CdTe polycrystal, in which 50 to 200 ppmwt of chlorine is doped, as a raw material.
    Type: Grant
    Filed: November 29, 2002
    Date of Patent: May 1, 2007
    Assignee: Nippon Mining & Metals Co., Ltd.
    Inventor: Ryuichi Hirano
  • Patent number: 7208043
    Abstract: A silicon semiconductor substrate has a structure possessing oxygen precipitate defects fated to form gettering sites in a high density directly below the defect-free region of void type crystals. The silicon semiconductor substrate is formed by heat-treating a silicon semiconductor substrate derived from a silicon single crystal grown by the Czochralski method or the magnetic field-applied Czochralski method and characterized by satisfying the relational expression (Oi DZ)?(COP DZ)?10 ?m wherein Oi DZ denotes a defect-free zone of oxygen precipitate crystal defects and COP DZ denotes a region devoid of a void type defect measuring not less than 0.11 ?m in size, and having not less than 5×108 oxygen precipitate crystal defects per cm3.
    Type: Grant
    Filed: September 6, 2002
    Date of Patent: April 24, 2007
    Assignee: Siltronic AG
    Inventors: Akiyoshi Tachikawa, Atsushi Ikari
  • Patent number: 7208042
    Abstract: 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: Grant
    Filed: January 30, 2004
    Date of Patent: April 24, 2007
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Kazuhiro Harada, Yoji Suzuki, Hidenobu Abe
  • Patent number: 7204881
    Abstract: 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: Grant
    Filed: July 8, 2003
    Date of Patent: April 17, 2007
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Ryoji Hoshi, Susumu Sonokawa
  • Patent number: 7201800
    Abstract: 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: Grant
    Filed: October 12, 2004
    Date of Patent: April 10, 2007
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Luciano Mule'Stagno, Jeffrey L. Libbert, Richard J. Phillips, Milind Kulkarni, Mohsen Banan, Stephen J. Brunkhorst
  • Patent number: 7198738
    Abstract: The present invention provides a cesium-lithium-borate crystal, which can be used as a high-performance wavelength converting crystal, having a chemical composition expressed as CsLiB6O10, and substituted cesium-lithium-borate crystals expressed by the following formula: Cs1?xLi1?yMx+yB6O10 or Cs2(1?z)Li2LzB12O20 (where, M is an alkali metal element, and L is an alkali earth metal element); a method for manufacturing same by heating and melting; and an optical apparatus using such crystals.
    Type: Grant
    Filed: December 23, 2005
    Date of Patent: April 3, 2007
    Assignee: Research Development Corporation of Japan
    Inventors: Takatomo Sasaki, Akio Hiraki, Yusuke Mori, Sadao Nakai
  • Patent number: 7195669
    Abstract: 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: Grant
    Filed: July 7, 2003
    Date of Patent: March 27, 2007
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Daisuke Wakabayashi, Masao Saito, Satoshi Sato, Jun Furukawa, Kounosuke Kitamura
  • Patent number: 7195671
    Abstract: 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: Grant
    Filed: September 24, 2004
    Date of Patent: March 27, 2007
    Assignee: Siemens Medical Solutions USA, Inc.
    Inventors: Olexy V. Radkevich, Dennis Persyk, Volodimir Protsenko
  • Patent number: 7195668
    Abstract: 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: Grant
    Filed: December 22, 2004
    Date of Patent: March 27, 2007
    Assignee: Siltronic AG
    Inventors: Yutaka Kishida, Teruyuki Tamaki
  • Patent number: 7179405
    Abstract: A material for harmonic generation has been made by substitutional changes to the crystal LaCa4 (BO3)3 also known as LaCOB in the form Re1xRe2yRe3zCa4(BO3)3O where Re1 and Re2, (rare earth ion 1 and rare earth ion 2) are selected from the group consisting of Sc, Yttrium, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu; Re3 is Lanthanum; and x+y+z=1.
    Type: Grant
    Filed: October 1, 2002
    Date of Patent: February 20, 2007
    Assignee: The Regents of the University of California
    Inventors: Christopher A. Ebbers, Kathleen I. Schaffers
  • Patent number: 7179330
    Abstract: The present invention is a method of manufacturing a silicon single crystal by Czochralski method without performing Dash Necking method, wherein a temperature variation at a surface of a silicon melt is kept at ±5° C. or less at least for a period from a point of bringing the tip end of a seed crystal into contact with the silicon melt to a point of shifting to pull the single crystal. Thereby, in a method of growing a silicon single crystal by Czochralski method without using Dash Necking method, a success ratio of growing a single crystal free from dislocation can be increased, at the same time a heavy silicon single crystal having a large diameter in which a diameter of a constant diameter portion is over 200 mm can be grown even in the case of growing a silicon single crystal having a crystal orientation of <110>.
    Type: Grant
    Filed: April 23, 2003
    Date of Patent: February 20, 2007
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Izumi Fusegawa, Sadayuki Okuni, Nobuaki Mitamura, Tomohiko Ohta, Nobuo Katuoka
  • Patent number: 7160386
    Abstract: A single crystal semiconductor manufacturing apparatus in which the concentration of oxygen in a single crystal semiconductor is controlled while pulling up a single crystal semiconductor such as single crystal silicon by the CZ method, a single crystal semiconductor manufacturing method, and a single crystal ingot manufactured by the method are disclosed. The natural convection (20) in the melt (5) in a quartz crucible (3) is controlled by regulating the temperatures at a plurality of parts of the melt (5). A single crystal semiconductor (6) can have a desired diameter by regulating the amount of heat produced by heating means (9a) on the upper side. Further the ratio between the amount of heat produced by the upper-side heating means (9a) and that by the lower-side heating means (9b) is adjusted to vary the process condition. In the adjustment, the amount of heat produced by the lower-side heating means (9b) is controlled to a relatively large proportion.
    Type: Grant
    Filed: September 27, 2002
    Date of Patent: January 9, 2007
    Assignee: Komatsu Denshi Kinzoku Kabushiki Kaisha
    Inventors: Yutaka Shiraishi, Jyunsuke Tomioka, Takuji Okumura, Tadayuki Hanamoto, Takehiro Komatsu, Shigeo Morimoto
  • Patent number: 7160387
    Abstract: This invention provides a high purity silica crucible having low impurity concentration in its inner portion, and its production method. The crucible, in which at least each content of Na and Li being contained in the depth of 1 mm from the inside surface is less than 0.05 ppm, is given by a production method of a high purity silica glass crucible, wherein a purity of the melted silica powder layer is increased by applying a voltage between a mold and an arc electrode to move impurity metals being contained in the melted silica glass layer to the outside, when the silica crucible is produced by arc plasma heating a raw material powder of silica in an inside surface of a hollow rotary mold. The method comprises, keeping an arc electrode potential of within ±500 V during an arc melting, applying a voltage of from ?1000 V to ?20000 V to a mold being insulated to the ground, and applying a high voltage to the un-melted silica powder layer of the outside.
    Type: Grant
    Filed: February 20, 2004
    Date of Patent: January 9, 2007
    Assignee: Japan Super Quartz Corporation
    Inventors: Hiroshi Kishi, Masanori Fukui, Yoshiyuki Tsuji
  • Patent number: 7147711
    Abstract: The present invention provides a method for producing a silicon wafer, which comprises growing a silicon single crystal ingot having a resistivity of 100 ?·cm or more and an initial interstitial oxygen concentration of 10 to 25 ppma and doped with nitrogen by the Czochralski method, processing the silicon single crystal ingot into a wafer, and subjecting the wafer to a heat treatment so that a residual interstitial oxygen concentration in the wafer should become 8 ppma or less, and a method for producing a silicon wafer, which comprises growing a silicon single crystal ingot having a resistivity of 100 ?·cm or more and an initial interstitial oxygen concentration of 8 ppma or less and doped with nitrogen by the Czochralski method, processing the silicon single crystal ingot into a wafer, and subjecting the wafer to a heat treatment to form an oxide precipitate layer in a bulk portion of the wafer, as well as silicon wafers produced by these production methods.
    Type: Grant
    Filed: September 14, 2001
    Date of Patent: December 12, 2006
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Masaro Tamatsuka, Wei Feig Qu, Norihiro Kobayashi
  • Patent number: 7147710
    Abstract: There is described a method which enables stable manufacture of a high-quality, ultra-thin epitaxial silicon wafer, as well as an epitaxial silicon wafer capable of bearing shipment manufactured by the method. A method of manufacturing an epitaxial silicon wafer having an ultra-thin epitaxial film, by means of forming an epitaxial film on a silicon wafer after having annealed the silicon wafer, includes the steps of: sufficiently smoothing COPs formed in the surface of the silicon wafer by means of appropriately setting annealing conditions according to an size of COPs in the vicinity of a surface of the silicon wafer; and forming an epitaxial film through epitaxial growth.
    Type: Grant
    Filed: November 18, 2002
    Date of Patent: December 12, 2006
    Assignee: Komatsu Denshi Kinzoku Kabushiki Kaisha
    Inventors: Kazuya Togashi, Masayoshi Danbata, Kuniaki Arai, Kaori Matsumoto
  • Patent number: 7141114
    Abstract: An improved process for producing a crystalline silicon ingot, a crystalline silicon wafer and a photovoltaic cell using the directional solidification process, and more particularly to loading and preparing a mold for the process of directional solidification. At least one rod polysilicon section and at least one chunk polysilicon, chip polysilicon or granular polysilicon is loaded into the mold, increasing packing density and thermal conductivity of the polysilicon contents while reducing contamination and resources expended to process a production cycle.
    Type: Grant
    Filed: June 30, 2004
    Date of Patent: November 28, 2006
    Assignee: REC Silicon Inc
    Inventors: Michael V. Spangler, Carl D. Seburn
  • Patent number: 7141113
    Abstract: A method for growing a silicon crystal by a Czochralsky method, wherein, let a pulling speed be V (mm/min) and an average value of an in-crystal temperature gradient in a pulling axis direction within a temperature range, a silicon melting point to 1350° C., be G (° C./mm), V/G ranges from 0.16 to 0.18 mm2/° C. min between a crystal center position and a crystal outer periphery position, and a ratio G outer/G center of an average value G of an in-crystal temperature gradient in a pulling axis direction within a temperature range, a silicon melting point to 1350° C., at a crystal outer surface to that at a crystal center is set to up to 1.10 to thereby obtain a high-quality perfect crystal silicon wafer. Such a perfect crystal silicon wafer, wherein an oxygen concentration is controlled to up to 13×1017 atoms/cm3, an initial heat treatment temperature is at least up to 500° C. and a temperature is raised at up to 1° C./min at least within 700 to 900° C.
    Type: Grant
    Filed: November 19, 1999
    Date of Patent: November 28, 2006
    Assignee: Komatsu Denshi Kinzoku Kabushiki Kaisha
    Inventors: Kozo Nakamura, Toshiaki Saishoji, Hirotaka Nakajima, Shinya Sadohara, Masashi Nishimura, Toshirou Kotooka, Yoshiyuki Shimanuki
  • Patent number: 7135069
    Abstract: An inexpensive method of coating silicon shot with boron atoms comprises (1) immersing silicon shot in an aqueous solution comprising a boric acid and polyvinyl alcohol, and (2) heating the solution so as to evaporate water and form a polymerized polyvinyl alcohol coating containing boron on the shot. A precise amount of this coated shot may then be mixed with a measured quantity of intrinsic silicon pellets and the resulting mixture may then be melted to provide a boron-doped silicon melt for use in growing p-type silicon bodies that can be converted to substrates for photovoltaic solar cells.
    Type: Grant
    Filed: March 4, 2004
    Date of Patent: November 14, 2006
    Assignee: Schott Solar, Inc.
    Inventor: Bernhard P. Piwczyk
  • Patent number: 7132060
    Abstract: Inventions relates to scintillation substances and they may be utilized in nuclear physics, medicine and oil industry for recording and measurements of X-ray, gamma-ray and alpha-ray, nondestructive testing of solid states structure, three-dimensional positron-emission tomography and X-ray tomography and fluorography. Substances based on silicate comprising lutetium and cerium characterized in that compositions of substances are represented by chemical formulae CexLu2+2y?xSi1?yO5+y, CexLiq+pLu2?p+2?y?x?zAzSi1?yO5+y?p, CexLiq+pLu9.33?x?p?z?0.67AzSi6O26?p, where A is at least one element selected from group consisting of Gd, Sc, Y, La, Eu, Tb, x is value between 1×10?4 f.units and 0.02 f.units., y is value between 0.024 f.units and 0.09 f.units, z is value does not exceeding 0.05 f.units, q is value does not exceeding 0.2 f.units, p is value does not exceeding 0.05 f.units.
    Type: Grant
    Filed: March 12, 2004
    Date of Patent: November 7, 2006
    Inventors: Alexander Iosifovich Zagumennyi, Yuri Dmitrievich Zavartsev, Sergei Alexandrovich Kutovoi
  • Patent number: 7132091
    Abstract: A single crystal silicon ingot having a constant diameter portion that contains arsenic dopant atoms at a concentration which results in the silicon having a resistivity that is less than about 0.003 ?·cm.
    Type: Grant
    Filed: September 27, 2002
    Date of Patent: November 7, 2006
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Milind Kulkarni, Mohsen Banan, Christopher V. Luers
  • Patent number: 7129123
    Abstract: In a method for producing an SOI wafer comprising steps of implanting ions from a bond wafer surface to form an ion-implanted layer inside the wafer, bonding the ion-implanted bond wafer surface and a surface of a base wafer via an oxide film or directly, and forming an SOI wafer by delaminating by heat treatment a part of the bond wafer at the ion-implanted layer, the bond wafer is a silicon wafer that consists of a silicon single crystal grown by Czochralski method, that is occupied by N region outside OSF generated in a ring shape and that has no defect region detected by Cu deposition method. Thereby, even an extremely thin SOI layer having a thickness of 200 nm or less, can provide an SOI wafer that has an excellent electric property without micro pits caused by acid cleaning, and can be produced without increasing the number of processes.
    Type: Grant
    Filed: October 24, 2003
    Date of Patent: October 31, 2006
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Masahiro Sakurada, Nobuaki Mitamura, Izumi Fusegawa, Tomohiko Ohta
  • Patent number: 7125450
    Abstract: The present invention is directed to a process for preparing single crystal silicon, in ingot or wafer form, wherein crucible rotation is utilized to control the average axial temperature gradient in the crystal, G0, as a function of radius (i.e., G0(r)), particularly at or near the central axis. Additionally, crucible rotation modulation is utilized to obtain an axially uniform oxygen content therein.
    Type: Grant
    Filed: October 31, 2003
    Date of Patent: October 24, 2006
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Zheng Lu, Steven L. Kimbel, Ying Tao
  • Patent number: 7122082
    Abstract: A silicon wafer wherein stacking fault (SF) nuclei are distributed throughout the entire in-plane direction, and the density of the stacking fault nuclei is set to a range of between 0.5×108 cm?3 and 1×1011 cm?3.
    Type: Grant
    Filed: November 13, 2003
    Date of Patent: October 17, 2006
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Takaaki Shiota, Yoshinobu Nakada
  • Patent number: 7105050
    Abstract: A process for the preparation of a silicon single ingot in accordance with the Czochralski method. The process for growing the single crystal silicon ingot comprises controlling (i) a growth velocity, v, (ii) an average axial temperature gradient, G0, during the growth of a constant diameter portion of the crystal over a temperature range from solidification to a temperature of no less than about 1325° C. to initially produce in the constant diameter portion of the ingot a series of predominant intrinsic point defects including vacancy dominated regions and silicon self interstitial dominated regions, alternating along the axis, and cooling the regions from the temperature of solidification at a rate which allows silicon self-interstitial atoms to diffuse radially to the lateral surface and to diffuse axially to vacancy dominated regions to reduce the concentration intrinsic point defects in each region.
    Type: Grant
    Filed: February 16, 2005
    Date of Patent: September 12, 2006
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Vladimir V. Voronkov, Robert J. Falster, Mohsen Banan
  • Patent number: 7097718
    Abstract: Epitaxial wafers comprising a single crystal silicon substrate comprising agglomerated vacancy defects and having an axially symmetric region in which silicon self-interstitials are the predominant intrinsic point defect and which is substantially free of agglomerated defects, and an epitaxial layer which is deposited upon a surface of the substrate and which is substantially free of grown-in defects caused by the presence of agglomerated intrinsic point defects on the substrate surface upon which the epitaxial layer is deposited.
    Type: Grant
    Filed: May 20, 2003
    Date of Patent: August 29, 2006
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Luciano Mule'Stagno, Lu Fei, Joseph C. Holzer, Harold W. Korb, Robert J. Falster
  • Patent number: 7097707
    Abstract: A method of making a single crystal GaN boule, comprising contacting a GaN seed wafer with a GaN source environment under process conditions including a thermal gradient in the GaN source environment producing growth of gallium nitride on the GaN seed wafer, thereby forming the GaN boule. The GaN source environment in various implementations includes gallium melt in an ambient atmosphere of nitrogen or ammonia, or alternatively, supercritical ammonia containing solubilized GaN. The method produces single crystal GaN boules >10 millimeters in diameter, of device quality suitable for production of GaN wafers useful in the fabrication of microelectronic, optoelectronic and microelectromechanical devices and device precursor structures therefor.
    Type: Grant
    Filed: December 23, 2002
    Date of Patent: August 29, 2006
    Assignee: Cree, Inc.
    Inventor: Xueping Xu