Having Pulling During Growth (e.g., Czochralski Method, Zone Drawing) Patents (Class 117/13)
  • Publication number: 20080210155
    Abstract: A silicon single crystal which has been produced using the Czochralski method has a <113> orientation.
    Type: Application
    Filed: February 28, 2008
    Publication date: September 4, 2008
    Applicant: SILTRONIC AG
    Inventors: Dirk Dantz, Wilfried Von Ammon, Dirk Zemke, Franz Segieth
  • Patent number: 7419545
    Abstract: The present invention provides a producing method with which large silicon carbide (SiC) single crystal can be produced at low cost. Silicon carbide single crystal is produced or grown by dissolving and reacting silicon (Si) and carbon (C) in an alkali metal flux. The alkali metal preferably is lithium (Li). With this method, silicon carbide single crystal can be produced even under low-temperature conditions of 1500° C. or lower, for example. The photograph of FIG. 3B is an example of a silicon carbide single crystal obtained by the method of the present invention.
    Type: Grant
    Filed: December 26, 2005
    Date of Patent: September 2, 2008
    Assignees: Matsushita Electric Industrial Co., Ltd., Osaka University
    Inventors: Yasuo Kitaoka, Yusuke Mori, Takatomo Sasaki, Fumio Kawamura, Minoru Kawahara
  • Publication number: 20080203361
    Abstract: A method and apparatus for growth of uniform multi-component single crystals is provided. The single crystal material has at least three elements and has a diameter of at least 50 mm, a dislocation density of less than 100 cm?1 and a radial compositional variation of less than 1%.
    Type: Application
    Filed: September 1, 2005
    Publication date: August 28, 2008
    Applicant: Rensselaer Polytechnic Institute
    Inventor: Partha Dutta
  • Patent number: 7416603
    Abstract: Disclosed is a method of growing a single crystal from a melt contained in a crucible. The method includes the step of making the temperature of a melt increase gradually to a maximum point and then decrease gradually along the axis parallel to the lengthwise direction of the single crystal from the interface of the single crystal and the melt to the bottom of the crucible. The increasing temperature of the melt is kept to preferably have a greater temperature gradient than the decreasing temperature thereof. Preferably, the axis is set to pass through the center of the single crystal. Preferably, the convection of the inner region of the melt is made smaller than that of the outer region thereof.
    Type: Grant
    Filed: October 19, 2005
    Date of Patent: August 26, 2008
    Assignee: Siltron Inc.
    Inventor: Hyon-Jong Cho
  • Patent number: 7416709
    Abstract: A method is provided that comprises having a trial generation station generate crystallization trials in a crystallization plate transporting the crystallization plate to an imaging station; and having the imaging station take images of the crystallization trials within 30 minutes of the formation of the crystallization trials; wherein the method is performed in a single automated system.
    Type: Grant
    Filed: December 16, 2004
    Date of Patent: August 26, 2008
    Assignee: Takeda San Diego, Inc.
    Inventors: Laurent Martin, John W. Palan
  • Patent number: 7416710
    Abstract: A crystallization system is provided that comprises a screen replicator having a transfer mechanism configured to transfer portions of different screen solutions contained in a screen storage plate to well regions of a crystallization plate; a screen storage station including a housing configured to store a plurality of screen storage plates and mechanics for retrieving a selected screen storage plate from among the plurality of screen storage plates for transport to the screen replicator; a transport mechanism configured to transport a screen storage plate retrieved by the screen storage station to the screen replicator; and a controller including logic for causing the screen storage station to retrieve the selected screen storage plate from among the plurality of screen storage plates, logic for causing the transport mechanism to transport the selected screen storage plate from the screen storage station to the screen replicator, and logic for causing the screen replicator to transfer portions of different
    Type: Grant
    Filed: December 1, 2004
    Date of Patent: August 26, 2008
    Assignee: Takeda San Diego, Inc.
    Inventors: Laurent Martin, John W. Palan
  • Patent number: 7413606
    Abstract: It is aimed at providing a fluoride crystal growing method capable of controlling a shape of the crystal by a micro-pulling-down method. Fluoride crystals in shapes depending on purposes, respectively, can be grown by adopting carbon, platinum, and iridium as crucible materials adaptable to fluorides, respectively, and by designing shapes of the crucibles taking account of wettabilities of the materials with the fluorides, respectively.
    Type: Grant
    Filed: July 20, 2004
    Date of Patent: August 19, 2008
    Assignees: Stella Chemifa Corporation, Fukuda Crystal Laboratory
    Inventors: Tomohiko Satonaga, Hirohisa Kikuyama, Tsuguo Fukuda
  • Publication number: 20080184928
    Abstract: The present invention is a method for producing a single crystal that is a multi-pulling method for pulling a plurality of single crystals 3 from a raw material melt 4 in a same crucible in a chamber by a Czochralski method, comprising steps of: pulling a single crystal 3 from a raw material melt 4; then additionally charging polycrystalline raw material in a residual raw material melt 4 without turning off power of a heater 7, and melting the polycrystalline raw material; then pulling a next single crystal 3; and repeating the steps and thereby pulling the plurality of single crystals 3; wherein in a case of setting a ratio of a pulling rate V and crystal temperature gradient G near a solid-liquid interface along a pulling axis direction when a straight body of the single crystal 3 is grown to be V/G, in order to control the V/G of each of the single crystals 3 to be pulled to a predetermined value, a pulling condition such as the pulling rate V is preliminarily modified according to an elapsed time from beg
    Type: Application
    Filed: October 21, 2005
    Publication date: August 7, 2008
    Applicant: SHIN-ETSU HANDOTAI CO., LTD.
    Inventors: Ryoji Hoshi, Takahiro Yanagimachi
  • Patent number: 7407866
    Abstract: An SOI wafer in which a base wafer and a bond wafer respectively consisting of silicon single crystal are bonded via an oxide film, and then the bond wafer is thinned to form a silicon active layer, wherein the base wafer is formed of silicon single crystal grown by Czochralski method, and the whole surface of the base wafer is within N region outside OSF region and doesn't include a defect region detected by Cu deposition method, or the whole surface of the base wafer is within a region outside OSF region, doesn't include a defect region detected by Cu deposition method, and includes I region containing dislocation cluster due to interstitial silicon. Thereby, there is provided an SOI wafer that retains high insulating properties and has an excellent electrical reliability in device fabrication even in the case of forming an extremely thin interlevel dielectric oxide film with, for example, a thickness of 100 nm or less.
    Type: Grant
    Filed: January 22, 2004
    Date of Patent: August 5, 2008
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Masahiro Sakurada, Nobuaki Mitamura, Izumi Fusegawa
  • Patent number: 7404856
    Abstract: The present invention relates to a process for forming single crystal silicon ingots or wafers that contain an axially symmetric region in which vacancies are the predominant intrinsic point defect, that are substantially free of oxidation induced stacking faults, and are nitrogen doped to stabilize oxygen precipitation nuclei therein.
    Type: Grant
    Filed: January 15, 2007
    Date of Patent: July 29, 2008
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Hiroyo Haga, Takaaki Aoshima, Mohsen Banan
  • Patent number: 7399428
    Abstract: Embodiments of the present invention are directed to compositions and processing methods of rare-earth vanadate based materials that have high emission efficiency in a wavelength range of 480 to 700 nm with the maximum intensity at 535 nm (bright yellow) under UV, X-ray and other forms of high-energy irradiation. Embodiments of the present invention are directed to general chemical compositions of the form (Gd1-xAx)(V1-yBy)(O4-zCz), where A is selected from the group consisting of Bi, Tl, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Lu for 0<x<0.2; B is Ta, Nb, W, and Mo for 0<y<0.1; and C is N, F, Br, and I for 0<z<0.1. Methods of preparation include sol gel, liquid flux, and co-precipitation processes.
    Type: Grant
    Filed: February 18, 2005
    Date of Patent: July 15, 2008
    Assignee: Intematix Corporation
    Inventors: Yi-Qun Li, Shifan Cheng, Ning Wang, Yi Dong, Xiao-Dong Sun
  • Patent number: 7396405
    Abstract: There is disclosed a single crystal obtained by a single crystal pulling method, wherein an interval of striations incorporated into the single crystal due to temperature fluctuation of crystal melt at the time of crystal growth is controlled, and a method of growing a single crystal according to a single crystal pulling method, wherein a growth rate and/or a temperature fluctuation period are controlled so that V×F/sin ? may be in a certain range when a growth rate at the time of growing a single crystal is defined as V (mm/min), a temperature fluctuation period of crystal melt is defined as F (min), and an angle to the level surface of a crystal-growth interface is defined as ?.
    Type: Grant
    Filed: September 8, 2003
    Date of Patent: July 8, 2008
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Ryoji Hoshi, Susumu Sonokawa
  • Patent number: 7396406
    Abstract: A single crystal semiconductor manufacturing method for realizing a dislocation-free single crystal while not varying or hardly varying electric power supplied to a heater when and after a seed crystal comes into contact with a melt. The allowable temperature difference ?Tc not causing dislocation in the seed crystal is determined according to the concentration (C) of the impurities added to the seed crystal (14) and the size (diameter D) of the seed crystal (14). When the seed crystal (14) comes into contact with the melt (5), electric power supplied to a bottom heater (19) is fixed, and a magnetic field produced by a magnet (20) is applied to the melt (5). Electric power supplied to a main heater (9) is controlled so that the temperature at the surface of the melt (5) which the seed crystal (14) comes into contact with may be a target value. After the seed crystal (14) comes into contact with the melt (5), single crystal silicon is pulled up without performing a necking process.
    Type: Grant
    Filed: February 9, 2004
    Date of Patent: July 8, 2008
    Assignee: Sumco Techxiv Corporation
    Inventors: Hiroshi Inagaki, Masahiro Shibata, Shigeki Kawashima, Nobuyuki Fukuda
  • Publication number: 20080151954
    Abstract: In a method of forming an Nd:YVO4 laser crystal, a melt of Nd:YVO4 in a vacuum is provided and an Nd:YVO4 seed crystal is provided in the vacuum with its c-axis oriented perpendicular to a surface of the melt. While in the vacuum, Nd:YVO4 from the melt is caused to adhere to the Nd:YVO4 seed crystal thereby forming an Nd:YVO4 boule with its c-axis oriented perpendicular to the surface of the melt. A portion of the boule can be removed therefrom to become an Nd:YVO4 laser crystal having no sub-grain boundaries and/or ghost veils in a cross section thereof perpendicular to the c-axis. This c-axis grown Nd:YVO4 crystal can be used as the lasing element of a laser.
    Type: Application
    Filed: July 12, 2007
    Publication date: June 26, 2008
    Applicant: II-VI Incorporated
    Inventors: Kelvin G. Lynn, Elgin E. Eissler, Xiaoming Li
  • Patent number: 7387676
    Abstract: In a process for producing silicon semiconductor wafers, a silicon single crystal is pulled using the Czochralski method and is processed to form semiconductor wafers, a ratio V/G of pulling rate V and axial temperature gradient G at a growth front during the pulling of the single crystal being controlled in such a manner that agglomerated vacancy defects above a critical size are formed in the single crystal, the agglomerated vacancy defects, in a region of the semiconductor wafer that is of relevance to electronic components, shrinking during production of the components such that the size in this region no longer exceeds the critical size. Silicon semiconductor wafers with agglomerated vacancy defects in the relevant device region preferably contain agglomerated vacancy defects having an inner surface which is at least partially free of an oxide layer and a size of less than 50 nm.
    Type: Grant
    Filed: June 14, 2006
    Date of Patent: June 17, 2008
    Assignee: Siltronic AG
    Inventors: Wilfried von Ammon, Walter Haeckl, Andreas Huber, Ulrich Lambert
  • Patent number: 7381392
    Abstract: The present invention relates to silicon feedstock for producing directionally solidified silicon ingots, thin sheets and ribbons for the production of silicon wafers for PV solar cells where the silicon feedstock contains between 0.2 and 10 ppma boron and between 0.1 and 10 ppma phosphorus distributed in the material. The invention further relates to directionally solidified silicon ingot or thin silicon sheet or ribbon for making wafers for solar cells containing between 0.2 ppma and 10 ppma boron and between 0.1 ppma and 10 ppma phosphorus distributed in the ingot, said silicon ingot having a type change from p-type to n-type or from n-type to p-type at a position between 40 and 99% of the ingot height or sheet or ribbon thickness and having a resistivity profile described by an exponential curve having a starting value between 0.4 and 10 ohm cm and where the resistivity value increases towards the type change point.
    Type: Grant
    Filed: January 12, 2004
    Date of Patent: June 3, 2008
    Assignee: Elkem AS
    Inventors: Erik Enebakk, Kenneth Friestad, Ragnar Tronstad, Cyrus Zahedi, Christian Dethloff
  • Patent number: 7381266
    Abstract: A sapphire crystal growth method includes a first step of grinding, a second step of purification, a third step of spraying and drying particles, a fourth step of adding organic bonding agent, a fifth step of press molding, and a sixth step of crystal growth. Thus, the sapphire crystal growth method has a shorter crystal growth time than that of the conventional crystal growth method. In addition, the sapphire crystal growth method has a lower price, has crystals whose mass and size are unlimited, and has a higher quality.
    Type: Grant
    Filed: December 27, 2006
    Date of Patent: June 3, 2008
    Inventor: Yu-Feng Chang
  • Patent number: 7378042
    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(B03)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, Th, Dy, Ho, Er, Tm, Yb, and Lu; Re3 is Lanthanum; and x+y+z=1.
    Type: Grant
    Filed: January 10, 2007
    Date of Patent: May 27, 2008
    Assignee: Lawrence Livermore National Security, LLC
    Inventors: Christopher A. Ebbers, Kathleen I. Schaffers
  • Patent number: 7378071
    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 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: July 7, 2005
    Date of Patent: May 27, 2008
    Assignee: Siltron Inc.
    Inventors: Hyon-Jong Cho, Cheol-Woo Lee, Hong-Woo Lee, Cheong Jin Soo, Kim Sunmi
  • Patent number: 7374741
    Abstract: In this method for growing a silicon single crystal, an ambient gas where a single crystal is grown contains a gas hydrogen-containing substance, and a silicon single crystal is grown at a pull rate to form a dislocation cluster defect occurrence region at least in a portion of a radial cross section of said silicon single crystal and at a pull rate which is slower than that to form an laser scattering tomography defect occurrence region, according to the Czochralski method. This silicon wafer is sampled from a straight body of the silicon single crystal grown using said method for growing a silicon single crystal, and the LPD density of LPD of 0.09 ?m or greater in the surface after 10 times of repetitions of the SC-1 cleaning is 0.1/cm2 or less.
    Type: Grant
    Filed: August 9, 2006
    Date of Patent: May 20, 2008
    Assignee: Sumco Corporation
    Inventors: Toshiaki Ono, Wataru Sugimura, Masataka Hourai
  • Patent number: 7364618
    Abstract: This silicon wafer is obtained from a silicon single crystal grown by the CZ method in a hydrogen-containing inert gas atmosphere, and is a completely grown-in defect-free wafer containing no COPs or dislocation clusters throughout the wafer in the thickness and radial directions thereof, and all the portions consist essentially of an interstitial rich region. This method for growing silicon single crystals includes pulling a silicon single crystal in a hydrogen-containing inert gas atmosphere so as to expand the range of the pull rate for the PI region, wherein the pulling of the silicon single crystal is conducted at a pull rate within this expanded range of the pull rate for the PI region so as to grow a body portion that is an interstitial rich region.
    Type: Grant
    Filed: August 24, 2005
    Date of Patent: April 29, 2008
    Assignee: Sumco Corporation
    Inventors: Masataka Hourai, Wataru Sugimura, Toshiaki Ono
  • Patent number: 7364715
    Abstract: A single crystal of alkaline earth metal fluoride is produced by a single crystal pulling method, has a straight barrel part diameter of not less than 17 cm, preferably has a straight barrel part length of not less than 5 cm, and has a light transmittance, as measured at a wavelength of 632.8 nm, of not less than 80%, preferably 90 to 98%. Further, the main crystal growth plane of the single crystal is the {111} plane or the {100} plane. The single crystal of alkaline earth metal fluoride has a large diameter as described above, and in spite that it is in an as-grown state, the peripheral surface is not opaque and the visible light transmittance is high. Therefore, evaluation of bubbles or inclusions in the crystal becomes feasible without performing complicated machining of the crystal, and from the single crystal, a large-sized optical material having advantageous properties such as high quality and high uniformity can be cut out.
    Type: Grant
    Filed: November 19, 2003
    Date of Patent: April 29, 2008
    Assignee: Tokuyama Corporation
    Inventors: Teruhiko Nawata, Nobuyuki Kuramoto, Hiroyuki Yanagi, Tsuguo Fukuda
  • Patent number: 7364617
    Abstract: A silicon carbide seeded sublimation method is disclosed. The method includes the steps of nucleating growth on a seed crystal growth face that is between about 1° and 10° off-axis from the (0001) plane of the seed crystal while establishing a thermal gradient between the seed crystal and a source composition that is substantially perpendicular to the basal plane of the off-axis crystal.
    Type: Grant
    Filed: February 5, 2007
    Date of Patent: April 29, 2008
    Assignee: Cree, Inc.
    Inventors: Stephan Mueller, Adrian Powell, Valeri F. Tsvetkov
  • Patent number: 7361218
    Abstract: The present invention relates to a method for fabricating a crystal fiber having different regions of polarization inversion, comprising the following steps: (a) providing a source material; (b) putting the source material into a fabricating apparatus; and (c) forming the crystal fiber from the source material, and applying an external electric field on the grown crystal fiber during the growth procedure of the crystal fiber so as to induce micro-swing of the crystal fiber for polarization inversion, whereby poling at the time a ferroelectric crystalline body is being formed, whereas the conventional methods are designed for poling a ferroelectric crystalline body after it has been formed.
    Type: Grant
    Filed: November 9, 2004
    Date of Patent: April 22, 2008
    Assignee: National Sun Yat-Sen University
    Inventors: Chia-Chang Kuo, Li-Min Lee, Yu-Chieh Cho, Sheng-Lung Huang, Sheng Bang Huang
  • Patent number: 7351283
    Abstract: A crystalline thin structure (104, 204, 404) is grown on a surface (108, 228) of a substrate (112, 208, 400) by depositing molecules (136, 220) from a molecular precursor to a lateral growth front (144, 224) of the structure using a crystal grower (116, 200). In one embodiment, the crystal grower comprises a solution (124) containing the molecular precursor in a solvent (140). Molecules are added to the lateral growth front by moving one or both of the free surface (120, 120?) of the solution and deposition surface relative to the other at a predetermined rate. In another embodiment, the crystal grower comprises a mask (212) that includes at least one opening (216). Precursor molecules are vacuum deposited via a molecular beam (236) at the growth front (228) of the crystalline thin structure (204) as one or both of the opening and surface are moved relative to the other at a predetermined rate.
    Type: Grant
    Filed: March 11, 2005
    Date of Patent: April 1, 2008
    Assignee: The University of Vermont and State Agricultural College
    Inventor: Randall L. Headrick
  • Patent number: 7351282
    Abstract: Cutting method of ingot into wafers along cleavage plane. Onto surface of single crystal ingot 10 is implanted ion beam 23 to generate lattice defects in a direction defined by the crystal axes that corresponds to the cleavage plane. Cleavage is generated by applying a shock by a knife edge to the position of the lattice having a cutting face as a cleavage plane. Production time of waters is reduced with a more numbers of sliced wafers from one ingot.
    Type: Grant
    Filed: May 7, 2003
    Date of Patent: April 1, 2008
    Assignee: Kabushiki Kaisha Y.Y.L.
    Inventor: Sataro Yamaguchi
  • Patent number: 7344689
    Abstract: A silicon wafer for an IGBT is produced by forming an ingot having an interstitial oxygen concentration [Oi] of not more than 7.0×1017 atoms/cm3 by the Czochralski method; doping phosphorus in the ingot by neutron beam irradiation to the ingot; slicing a wafer from the ingot; performing annealing of the wafer in an oxidizing atmosphere containing at least oxygen at a temperature satisfying a predetermined formula; and forming a polysilicon layer or a strained layer on one side of the wafer.
    Type: Grant
    Filed: June 7, 2006
    Date of Patent: March 18, 2008
    Assignee: Sumco Corporation
    Inventors: Shigeru Umeno, Yasuhiro Oura, Koji Kato
  • Patent number: 7344594
    Abstract: A method of charging a crystal forming apparatus with molten source material is provided. The method includes the steps of positioning a melter assembly relative to the crystal forming apparatus for delivering molten silicon to a crucible of the apparatus. An upper heating coil in the melter assembly is operated to melt source material in a melting crucible. A lower heating coil in the melter assembly is operated to allow molten source material to flow through an orifice of the melter assembly to deliver a stream of molten source material to the crucible of the crystal forming apparatus. The invention is also directed to a method of charging a crystal puller with molten silicon including the step of removing an upper housing of the crystal puller defining a pulling chamber from a lower housing of the crystal puller defining a growth chamber and attaching the lower housing in place of the upper housing.
    Type: Grant
    Filed: June 17, 2005
    Date of Patent: March 18, 2008
    Assignee: MEMC Electronic Materials, Inc.
    Inventor: John Davis Holder
  • Patent number: 7341787
    Abstract: The invention relates to a process for producing highly doped semiconductor wafers, in which at least two dopants which are electrically active and belong to the same group of the periodic system of the elements are used for the doping. The invention also relates to a semiconductor wafer which is free of dislocations and is doped with at least two electrically active dopants which belong to the same group of the periodic system of the elements.
    Type: Grant
    Filed: January 26, 2005
    Date of Patent: March 11, 2008
    Assignee: Siltronic AG
    Inventors: Rupert Krautbauer, Erich Gmeilbauer, Robert Vorbuchner, Martin Weber
  • Patent number: 7332028
    Abstract: The invention relates to the handling of a composition comprising a rare-earth halide, especially within the context of the growth of crystals from said composition, said crystals generally being of formula AeLnfX(3f+e) in which Ln represents one or more rare earths, X represents one or more halogen atoms chosen from Cl, Br or I, and A represents one or more alkaline metals such as K, Li, Na, Rb or Cs, e and f representing values such that e, which may be zero, is less than or equal to 2f and f is greater than or equal to 1. It is possible in this way to grow single crystals exhibiting remarkable scintillation properties.
    Type: Grant
    Filed: June 11, 2003
    Date of Patent: February 19, 2008
    Assignee: Saint-Gobain Cristaux et Detecteurs
    Inventors: Alain Iltis, Vladimir Ouspenski
  • Patent number: 7329317
    Abstract: The present invention is to produce a silicon crystal wherein the boron concentration in the silicon crystal and the growth condition V/G are controlled so that the boron concentration in the silicon crystal is no less than 1×1018 atoms/cm3 and the growth condition V/G falls within the epitaxial defect-free region ?2 whose lower limit line LN1 is the line indicating that the growth rate V gradually drops as the boron concentration increases. A silicon wafer is also produced wherein the boron concentration in the silicon crystal and the growth condition V/G are controlled so as to include at least the epitaxial defect region ?1, and both the heat treatment condition and the oxygen concentration of the silicon crystal are controlled so that no OSF nuclei grow to OSFs.
    Type: Grant
    Filed: October 31, 2003
    Date of Patent: February 12, 2008
    Assignee: Komatsu Denshi Kinzoku Kabushiki Kaisha
    Inventors: Susumu Maeda, Hiroshi Inagaki, Shigeki Kawashima, Shoei Kurosaka, Kozo Nakamura
  • Patent number: 7326658
    Abstract: The present invention provides a method for producing a nitrogen-doped annealed wafer, wherein before a wafer sliced from a silicon single crystal doped with at least nitrogen and polished is subjected to a high temperature heat treatment at 1100° C. to 1350° C. in an atmosphere of argon, hydrogen or a mixed gas thereof, a step of maintaining the wafer at a temperature lower than the treatment temperature of the high temperature heat treatment is conducted to allow growth of oxygen precipitation nuclei having such a size that the nuclei should be annihilated by the high temperature heat treatment to such a size that the nuclei should not be annihilated by the high temperature heat treatment, and then the high temperature heat treatment is performed.
    Type: Grant
    Filed: May 22, 2002
    Date of Patent: February 5, 2008
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Makoto Iida, Masaro Tamatsuka
  • Patent number: 7323048
    Abstract: A method for producing a single crystal in which when the single crystal is grown by Czochralski method, V/G is controlled by controlling a fluctuation of a temperature gradient G of the crystal which is being pulled without lowering a pulling rate V, thereby the single crystal including a desired defect region over a whole plane in a radial direction of the crystal entirely in a direction of the crystal growth axis can be produced effectively for a short time at a high yield.
    Type: Grant
    Filed: May 28, 2004
    Date of Patent: January 29, 2008
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Masahiro Sakurada, Makoto Iida, Nobuaki Mitamura, Atsushi Ozaki
  • Patent number: 7320731
    Abstract: A process for growing a silicon single crystal which is capable of growing a silicon single crystal at a pulling rate which is not lower than the critical pulling rate at which an OSF-generating region will be generated is provided. Such a process for growing a silicon single crystal is characterized by using an atmospheric gas for growing a single crystal which is a hydrogen-containing gas which contains a hydrogen-containing substance, and pulling the silicon single crystal at a pulling rate ranging from a value with which the ratio (a/b) of the diameter (b) of the silicon single crystal and the outer diameter (a) of a ring which consists of the OSF-generating region in the radial direction of the silicon single crystal is not higher than 0.77 to another value with which the OSF-generating region disappears at the center part of the crystal.
    Type: Grant
    Filed: July 17, 2006
    Date of Patent: January 22, 2008
    Assignee: Sumco Corporation
    Inventors: Toshiaki Ono, Wataru Sugimura, Masataka Hourai
  • Publication number: 20080011222
    Abstract: The crucible and the side heater are held in the respective initial positions, and the raw material is put into the crucible. These initial positions are positions where the crucible side surface is mainly heated by the side heater. When the side heater heats the crucible side surface, the raw material is melted to form melt. When a part or all of the raw material is melted, the crucible is raised from the initial position or the side heater is lowered from the initial position. At this time, the position of the crucible or the side heater is adjusted such that the amount of heat applied to the lower side curved portion of the crucible side surface is greater than that in the initial relative position between the crucible and the side heater.
    Type: Application
    Filed: July 10, 2007
    Publication date: January 17, 2008
    Applicant: Sumco Techxiv Kabushiki Kaisha
    Inventors: Koichi Shimomura, Eiichirou Kotoura, Hiroyuki Ohta
  • Patent number: 7314522
    Abstract: An apparatus having a crucible (1) for holding a raw material, a heating means (11) for heating the raw material in the crucible (1) and a crystal transporting means (17) for transporting a seed crystal (13) upwards from the inside of the crucible (1), which further comprises a heat conducting member (3) which extends upwards at least from the vicinity of the upper end of the crucible (1), surrounds a single crystal (15) formed, and is made of a material having heat conductivity, and an interface portion radiation heat blocking member (7) for blocking, at least during cooling after the formation of a single crystal, the radiation heat toward an upper portion above the interface between a taper portion (15a) of the formed single crystal (15) connecting with the seed crystal (13) and a straight bulge portion (15b) having a cylindrical shape connecting with the taper portion (15a) of the formed single crystal (15).
    Type: Grant
    Filed: June 12, 2003
    Date of Patent: January 1, 2008
    Assignee: Hitachi Chemical Co., Ltd.
    Inventors: Shigeki Hirasawa, Masato Ikegawa, Hiroyuki Ishibashi, Akihiro Gunji
  • Patent number: 7311772
    Abstract: Means for supplying raw material in additional charging or recharging of solid granular raw material into molten material in the crucible, comprises a raw material supply tube to be filled with said material, a metallic support member which runs through the inside of the tube, connects with the bottom lid, and serves for descending the lid and for ascending the tube and the lid, and a configuration avoiding metallic contamination, whereby the lower-end aperture of the tube is opened for charging said material therein into the crucible in uniform circumferential distribution and in large quantity, thus achieving efficient supply operation to be widely applied for growing silicon single crystals.
    Type: Grant
    Filed: September 20, 2005
    Date of Patent: December 25, 2007
    Assignee: Sumco Corporation
    Inventors: Katsunori Nakashima, Koji Toma, Manabu Moroishi
  • Patent number: 7311888
    Abstract: The present invention provides an annealed wafer which has a wafer surface layer serving as a device fabricating region and having an excellent oxide film dielectric breakdown characteristic, and a wafer bulk layer in which oxide precipitates are present at a high density at the stage before the wafer is loaded into the device fabrication processes to give an excellent IG capability, and a method for manufacturing the annealed wafer. The present invention is directed to an annealed wafer obtained by performing heat treatment on a silicon wafer manufactured from a silicon single crystal grown by the Czochralski method, wherein a good chip yield of an oxide film dielectric breakdown characteristic in a region having at least a depth of up to 5 ?m from a wafer surface is 95% or more, and a density of oxide precipitates detectable in the wafer bulk and each having a size not smaller than a size showing a gettering capability is not less than 1×109/cm3.
    Type: Grant
    Filed: September 29, 2003
    Date of Patent: December 25, 2007
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Hiroshi Takeno, Masahiro Sakurada, Takeshi Kobayashi
  • Patent number: 7309393
    Abstract: Bulk Aluminum Antimonide (AlSb)-based single crystal materials have been prepared for use as ambient (room) temperature X-ray and Gamma-ray radiation detection.
    Type: Grant
    Filed: January 21, 2005
    Date of Patent: December 18, 2007
    Assignee: Lawrence Livermore National Security, LLC
    Inventors: John W. Sherohman, Arthur W. Coombs, III, Jick H. Yee
  • Patent number: 7294196
    Abstract: In a method for producing a silicon single crystal by Czochralski method, the single crystal is grown with controlling a growth rate between a growth rate at a boundary where a defect region detected by Cu deposition remaining after disappearance of OSF ring disappears when gradually decreasing a growth rate of silicon single crystal during pulling and a growth rate at a boundary where a high oxygen precipitation Nv region having a density of BMDs of 1×107 numbers/cm3 or more and/or a wafer lifetime of 30 ?sec or less after oxygen precipitation treatment disappears when gradually decreasing the growth rate further. Thereby, there is provided a silicon single crystal which does not belong to any of V region rich in vacancy, OSF region and I region rich in interstitial silicon, and has excellent electrical characteristics and gettering capability, so that yield of devices can be surely improved, and also an epitaxial wafer.
    Type: Grant
    Filed: May 7, 2003
    Date of Patent: November 13, 2007
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Masahiro Sakurada, Nobuaki Mitamura, Izumi Fusegawa, Tomohiko Ohta
  • Publication number: 20070240629
    Abstract: The present invention relates to a method for manufacturing a silicon single crystal by pulling up the silicon single crystal from a molten silicon by the CZ method, comprising: a cooling step of cooling the silicon single crystal by a cooler surrounding the silicon single crystal, and a heat shield body disposed surrounding an outer side and a lower side of the cooler while the silicon single crystal is being pulled up; and an Ms adjusting step of determining, in advance, an allowable range of a pulling speed at which a silicon single crystal having few crystal defects can be obtained by adjusting a distance (referred to “Ms”) from the lower surface of the heat shield body disposed on the lower side of the cooler to the surface of the molten silicon, wherein the silicon single crystal 11 is pulled up at a pulling speed within the allowable range thus determined.
    Type: Application
    Filed: April 10, 2007
    Publication date: October 18, 2007
    Inventors: Toshirou Kotooka, Takashi Yokoyama, Kazuyoshi Sakatani, Toshiaki Saishoji, Koichi Shimomura, Ryota Suewaka
  • Patent number: 7282190
    Abstract: A solar cell is produced by dipping a multicrystalline silicon substrate 28 in a solution 24 containing silicon, growing a silicon layer on the substrate 28 while decreasing with time the temperature drop rate of the solution during the dipping of the substrate in the solution, and forming a pn junction in the silicon layer. Thereby, there is provided a silicon layer production method that can form a thick layer while restraining the degree of roughness, whereby a low-cost, multicrystalline-silicon solar cell production method is provided that realizes both a large current and a high FF.
    Type: Grant
    Filed: May 17, 2005
    Date of Patent: October 16, 2007
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masaki Mizutani, Shoji Nishida, Katsumi Nakagawa
  • Patent number: 7282094
    Abstract: To precisely predict the distribution of densities and sizes of void defects comprising voids and inner wall oxide membranes in a single crystal. The computer-based simulation determines, at steps 1 to 7, the distribution of temperatures within a single crystal 14 growing from a melt 12 from the time of its pulling-up to the time of its completing cooling with due consideration paid to convection currents in the melt 12. The computer-based simulation, at steps 8 to 15, determines the density of voids considering the cooling process of the single crystal separated from the melt, that is, the pulling-up speed of the single crystal after the separation from the melt, and reflecting the effect of slow and rapid cooling of the single crystal in the result, and relates the radius of voids with the thickness of inner wall oxide membrane developed around the voids.
    Type: Grant
    Filed: May 30, 2003
    Date of Patent: October 16, 2007
    Assignee: Sumco Corporation
    Inventors: Kounosuke Kitamura, Jun Furukawa, Naoki Ono
  • Publication number: 20070227439
    Abstract: A method for controlling the temperature gradient on the side surface of a silicon single crystal, the height of a solid-liquid interface, and the oxygen concentration in the longitudinal direction of the silicon single crystal is provided in order to manufacture a defect-free silicon single crystal whose oxygen concentration is controlled to a predetermined value rapidly and stably. By disposing a cylindrical cooler around the silicon single crystal, and adjusting the pulling speed of the silicon single crystal, the rotation speed of a crucible that stores molten silicon and the rotation speed of the silicon single crystal, and the output ratio of a multi-heater separated into at least two in the longitudinal direction of the silicon single crystal disposed around the crucible, the temperature gradient on the side surface, the height of the solid-liquid interface, and the oxygen concentration in the longitudinal direction of the silicon single crystal are controlled.
    Type: Application
    Filed: March 27, 2007
    Publication date: October 4, 2007
    Inventors: Takashi Yokoyama, Toshiaki Saishoji, Toshirou Kotooka, Kazuyoshi Sakatani
  • Publication number: 20070215033
    Abstract: There is provided a group III nitride crystal growth method capable of obtaining a material which is a GaN substrate of low defect density capable of being used as a power semiconductor substrate and in which characteristics of n-type and p-type requested for formation of transistor or the like. A growth method of group III nitride crystals includes: forming a mixed melt containing at least group III element and a flux formed of at least one selected from the group consisting of-alkaline metal and alkaline earth metal, in a reaction vessel; and growing group III nitride crystals from the mixed melt and a substance containing at least nitrogen, wherein after immersing a plurality of seed crystal substrates placed in an upper part of the reaction vessel in which the mixed melt is formed, into the mixed melt to cause crystal growth, the plurality of seed crystal substrates are pulled up above the mixed melt.
    Type: Application
    Filed: March 14, 2007
    Publication date: September 20, 2007
    Applicant: NGK Insulators, Ltd.
    Inventors: Minoru IMAEDA, Yoshimasa Kondo, Ichiro Okazaki
  • Patent number: 7264674
    Abstract: An apparatus is used to pull a single crystal, wherein a flow of an inert gas to the single crystal to be grown, a pressure in an apparatus body, and a temperature environment are always kept constant by keeping a melt level at a prescribed position in spite of changes in volume of a quartz crucible between batches and thermal deformation of the quartz crucible, so that high quality single crystals can be pulled.
    Type: Grant
    Filed: August 24, 2004
    Date of Patent: September 4, 2007
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Keiichi Takanashi, Tokuji Maeda, Ken Hamada
  • Patent number: 7264750
    Abstract: When produced as a single crystal ingot, a rare earth silicate single crystal 1 can be formed by cutting out from the single crystal ingot. The single crystal 1 has a crystal face F100 whose Miller indices can be determined by X-ray diffraction. The crystal face F100 is composed of a plurality of smooth partial region surfaces (for example, the partial region surface f100A and partial region surface f100B), the plurality of partial region surfaces each have an area detectable by X-ray diffraction, and the angles ? formed between the normal vectors of the plurality of partial region surfaces satisfy the following inequality: 0.1°???2.0°.
    Type: Grant
    Filed: July 26, 2004
    Date of Patent: September 4, 2007
    Assignee: Hitachi Chemical Co., Ltd.
    Inventors: Kazuhisa Kurashige, Naoaki Shimura, Hiroyuki Ishibashi, Akihiro Gunji, Mitsushi Kamada
  • Publication number: 20070193501
    Abstract: In this silicon single crystal wafer for IGBT, COP defects and dislocation clusters are eliminated from the entire region in the radial direction of the crystal, the interstitial oxygen concentration is 8.5×1017 atoms/cm3 or less, and variation in resistivity within the wafer surface is 5% or less. This method for manufacturing a silicon single crystal wafer for IGBT includes introducing a hydrogen atom-containing substance into an atmospheric gas at a hydrogen gas equivalent partial pressure of 40 to 400 Pa, and growing a single crystal having an interstitial oxygen concentration of 8.5×1017 atoms/cm3 or less at a silicon single crystal pulling speed enabling pulling of a silicon single crystal free of grown-in defects. The pulled silicon single crystal is irradiated with neutrons so as to dope with phosphorous; or an n-type dopant is added to the silicon melt; or phosphorous is added to the silicon melt so that the phosphorous concentration in the silicon single crystal is 2.9×1013 to 2.
    Type: Application
    Filed: February 20, 2007
    Publication date: August 23, 2007
    Inventors: Toshiaki Ono, Shigeru Umeno, Wataru Sugimura, Masataka Hourai
  • Patent number: 7260124
    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(B03)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: January 10, 2007
    Date of Patent: August 21, 2007
    Assignee: The Regents of the University of California
    Inventors: Christopher A. Ebbers, Kathleen I. Schaffers
  • Patent number: 7258744
    Abstract: The present invention discloses a graphite heater for producing a single crystal used when producing a single crystal by the Czochralski method which comprises at least a terminal part to which electric current is supplied and a cylindrical heat generating part by resistance heating and are provided so as to surround a crucible for containing a raw material melt wherein the heat generating part has heat generating slit parts formed by being provided with upper slits extending downward from the upper end and lower slits extending upwards from the lower end by turns, and a length of at least one slit of the upper slits differs from others and/or a length of at least one slit of the lower slits differs from others so that a heat generating distribution of the heat generating part may be changed.
    Type: Grant
    Filed: December 8, 2003
    Date of Patent: August 21, 2007
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Masahiro Sakurada, Izumi Fusegawa, Satoshi Soeta, Makoto Iida