With Responsive Control Patents (Class 117/15)
  • 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: 20080134958
    Abstract: An improved system based on the Czochralski process for continuous growth of a single crystal ingot comprises a low aspect ratio, large diameter, and substantially flat crucible, including an optional weir surrounding the crystal. The low aspect ratio crucible substantially eliminates convection currents and reduces oxygen content in a finished single crystal silicon ingot. A separate level controlled silicon pre-melting chamber provides a continuous source of molten silicon to the growth crucible advantageously eliminating the need for vertical travel and a crucible raising system during the crystal pulling process. A plurality of heaters beneath the crucible establish corresponding thermal zones across the melt. Thermal output of the heaters is individually controlled for providing an optimal thermal distribution across the melt and at the crystal/melt interface for improved crystal growth. Multiple crystal pulling chambers are provided for continuous processing and high throughput.
    Type: Application
    Filed: February 25, 2005
    Publication date: June 12, 2008
    Applicant: SOLAICX, INC
    Inventor: David L Bender
  • Patent number: 7368011
    Abstract: The apparatus for manufacturing a silicon single crystal includes: a crucible for storing molten silicon; a pulling-up device for pulling up a silicon single crystal from the molten silicon in the crucible to grow; a detecting device for detecting a position of the crucible in a vertical direction; and a control device for controlling a pulling rate for the silicon single crystal by the pulling-up device, based on the detected position of the crucible.
    Type: Grant
    Filed: July 29, 2005
    Date of Patent: May 6, 2008
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Youji Suzuki, Satoshi Sato
  • Patent number: 7361219
    Abstract: The present invention are a method for producing a silicon wafer having a crystal orientation <110> from a silicon single crystal ingot grown by a Floating Zone method (FZ method), wherein, at least, an FZ silicon single crystal ingot is grown by being made to be dislocation-free by Dash Necking method using a seed crystal having its crystal axis inclined at a specified angle from a crystal orientation <110>, and the grown FZ silicon single crystal ingot is sliced at the just angle of a crystal orientation <110> to produce a silicon wafer having a crystal orientation <110>, and a silicon wafer produced by the method. Thereby, there are provided a method for producing a silicon wafer having a crystal orientation <110> from a silicon single crystal ingot made to be dislocation-free at a high success rate by using Dash Necking method by FZ method, and a silicon wafer having an crystal orientation <110>.
    Type: Grant
    Filed: July 12, 2004
    Date of Patent: April 22, 2008
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventor: Ken Yoshizawa
  • 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: 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: 7326292
    Abstract: The inventive quality evaluation method for a single crystal ingot generally includes a step of determining cropping and sampling positions and a step of evaluating a sample. The step of determining cropping and sampling positions includes: (a) inputting basic information on the decision of cropping, sampling and prime positions according to equipments and products, (b) predetermining the cropping, sampling and prime positions according to the basic information, (c) monitoring a growing process of a growing ingot and analyzing/storing X factors related with the growing process of the growing ingot, and (d) determining the cropping and sampling positions based on the X factors related with the growing process.
    Type: Grant
    Filed: June 14, 2006
    Date of Patent: February 5, 2008
    Assignee: Siltron Inc.
    Inventors: Jin Geun Kim, Hyon Jong Cho
  • 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: 7314523
    Abstract: A method for manufacturing a SiC single crystal from a SiC seed crystal is provided. The method includes the steps of: measuring a diameter of the SiC single crystal during a crystal growth of the SiC single crystal; and controlling the diameter of the SiC single crystal to be a predetermined diameter on the basis of the measured diameter. The method provides the SiC single crystal with high quality and large size.
    Type: Grant
    Filed: August 26, 2005
    Date of Patent: January 1, 2008
    Assignee: DENSO CORPORATION
    Inventors: Kouki Futatsuyama, Yasuo Kitou
  • 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
  • Publication number: 20070277727
    Abstract: The liquid surface position of the melt in the crucible in the silicon single crystal growth process utilizing the Czochralski method is monitored using the melt surface position on the occasion of seeding as a reference position and an estimated melt surface position can be calculated according to every situation, so that the distance between the melt and the thermal shield or water-cooling structure can be controlled with high precision. When the estimated melt surface position passes a preset upper limit and approaches the thermal shield, an alarm goes off and, further, when the melt comes into contact with the thermal shield or approaches the water-cooling structure, an alarm goes off if desired and, at the same time, the crucible is forcedly stopped from moving, so that a serious accident such as steam-incurred explosion resulting from the melt coming into contact with the water-cooling structure can be prevented.
    Type: Application
    Filed: May 25, 2007
    Publication date: December 6, 2007
    Inventors: Hiroshi Hayakawa, Tokuji Maeda
  • Patent number: 7291221
    Abstract: A method and system for use in combination with a crystal growing apparatus for growing a monocrystalline ingot according to a Czochralski process. The crystal growing apparatus has a heated crucible including a semiconductor melt from which the ingot is pulled. The ingot is grown on a seed crystal pulled from the melt. A time varying external magnetic field is imposed on the melt during pulling of the ingot. The magnetic field is selectively adjusted to produce pumping forces in the melt to control a melt flow velocity while the ingot is being pulled from the melt.
    Type: Grant
    Filed: December 30, 2004
    Date of Patent: November 6, 2007
    Assignee: MEMC Electronic Materials, Inc.
    Inventor: Harold W Korb
  • 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: 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
  • 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: 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
  • 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: 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: 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: 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: 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: 7172656
    Abstract: In a device and a method for measuring the position of the liquid surface of a melt while a single crystal is being pulled, two measuring-lines are defined in an image of a fusion ring which is captured by means of a two-dimensional CCD camera, the intersections of the respective measuring lines and the fusion ring, on the opposite sides of the fusion ring, are detected, and the central position of the single crystal is calculated based on the intervals between the intersections on the opposite sides of the fusion ring, whereby the position of the liquid surface of the melt is determined.
    Type: Grant
    Filed: April 13, 2004
    Date of Patent: February 6, 2007
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Keiichi Takanashi, Nobumitsu Takase
  • 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: 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: 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: 7074271
    Abstract: A surface of a reference sample is contaminated with a transition metal, and a heat treatment is performed to diffuse the transition metal in the sample. A concentration of recombination centers formed by the transition metal is measured in the entire heat-treated reference sample, and a region [V], a region [Pv], a region [Pi], and a region [I] in the reference sample are defined based on the values measured. Meanwhile, recombination lifetimes associated with the transition metal are measured in the entire heat-treated reference sample. Based on both of the measurement results, a correlation line of the concentration of recombination centers and the recombination lifetimes is produced. A surface of the measurement sample is contaminated with the transition metal, and a heat treatment is performed to diffuse the transition metal in the sample.
    Type: Grant
    Filed: February 23, 2004
    Date of Patent: July 11, 2006
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Jun Furukawa, Kazunari Kurita, Kazuhiro Harada
  • Patent number: 7067007
    Abstract: The process for growing single crystals, wherein crystal material is melted in a crucible and a crystal nucleus is immersed in the molten crystal material and slowly pulled out, wherein the crystal formed during the pulling is kept at a temperature close to melting temperature of the output material. The invention also includes a device for practicing the above process.
    Type: Grant
    Filed: August 22, 2003
    Date of Patent: June 27, 2006
    Assignee: Schott Glas
    Inventors: Lothar Ackermann, Daniel Rytz, Klaus Dupre
  • Patent number: 7014704
    Abstract: A method for growing a silicon single crystal used for semiconductor integrated circuit devices, wherein the single crystal is grown by the CZ method at a nitrogen concentration of 1×1013 atoms/cm3–1×1015 atoms/cm3 with a cooling rate of not less than 2.5° C./min at a crystal temperature of 1150° C.–1000° C., in which case, the pulling rate is adjusted such that the outside diameter of a circular region including oxidation-induced stacking faults generated at the center of a wafer which is subjected to the oxidation heat treatment at high temperature is not more than ? of the wafer diameter, wherein the wafer is prepared by slicing the grown single crystal. In the growth method, the concentration of oxygen in the silicon single crystal is preferably not more than 9×1017 atoms/cm3 (ASTM '79). With this method, the silicon single crystal, in which the generation of Grown-in defects can be effectively suppressed, can be produced in a simple process without any increase in the production cost.
    Type: Grant
    Filed: June 6, 2003
    Date of Patent: March 21, 2006
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Toshiaki Ono, Tadami Tanaka, Shigeru Umeno, Eiichi Asayama, Hideshi Nishikawa
  • Patent number: 6997986
    Abstract: A method for preparing a high-quality garnet single crystal represented by the composition formula CaxNbyGazO12 (2.9<x<3.1, 1.6<y<1.8, 3.1<z<3.3) is provided. The single crystal can preferably be used as a single crystal substrate for forming a defect-free single crystal of bismuth-substituted rare-earth iron garnet thereon by liquid-phase epitaxial deposition. The method is to prepare a single crystal by the Czochralski technique, the single crystal having a garnet structure being represented by the composition formula CaxNbyGazO12 (2.9<x<3.1, 1.6<y<1.8, 3.1<z<3.3). The crystal is grown at a crystal growth rate g less than or equal to 1.72 mm/h. The crystal is preferably grown in an atmosphere containing oxygen 0.4% or more by volume and below 10.0% by volume.
    Type: Grant
    Filed: January 8, 2004
    Date of Patent: February 14, 2006
    Assignee: TDK Corporation
    Inventor: Jun Sato
  • Patent number: 6960254
    Abstract: A method and apparatus for controlling the quenching rate of a monocrystalline ingot pulled from a melt by adjusting one or more post growth processing parameter. A temperature model generates a temperature profile that represents the surface temperature along the length of the ingot at the instant it is pulled from the melt. A first temperature at a particular location along the length of the crystal is determined from the temperature profile. A temperature sensor senses a second temperature at the same particular location. A PLC calculates a quenching rate of the crystal as a function of the first temperature and the second temperature. The PLC generates an error between a target quenching rate and a calculated quenching rate, and one or more post growth process parameters are adjusted as function of the error signal to optimize the quenching rate.
    Type: Grant
    Filed: July 21, 2003
    Date of Patent: November 1, 2005
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Zheng Lu, Steven L. Kimbel
  • Patent number: 6942733
    Abstract: A fluid sealing system is provided for use in a crystal puller for growing a monocrystalline ingot. The crystal puller has a housing, a fluid flow path contained in the housing, and a fluid passage through a wall of the housing for passage of fluid. The fluid sealing system includes a fluid connector head adapted for connection to the fluid passage and to the fluid flow path to establish fluid communication between the fluid flow path and the outside of the housing. The head has a port adapted for fluid communication with the fluid passage through the wall of the housing. First and second seals around the port are adapted for sealing engagement with the head. A space is defined generally between the first and second seals, and a leak detector is arranged to monitor the space for detecting fluid leakage past at least one of the seals.
    Type: Grant
    Filed: June 19, 2003
    Date of Patent: September 13, 2005
    Assignee: MEMC Electronics Materials, Inc.
    Inventors: Carl F. Cherko, Robert D. Cook
  • Patent number: 6913647
    Abstract: A process for producing silicon which is substantially free of agglomerated intrinsic point defects in an ingot having a vacancy dominated region. An ingot is grown generally in accordance with the Czochralski method. While intrinsic point defects diffuse from or are annihilated within the ingot, at least a portion of the ingot is maintained above a temperature TA at which intrinsic point defects agglomerate. The achievement of defect free silicon is thus substantially decoupled from process parameters, such as pull rate, and system parameters, such as axial temperature gradient in the ingot.
    Type: Grant
    Filed: May 13, 2003
    Date of Patent: July 5, 2005
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Robert J. Falster, Harold W. Korb
  • Patent number: 6913646
    Abstract: There can be provided a silicon single crystal wafer grown according to Czochralski method wherein the whole plane of the wafer is occupied by N region on the outside of OSF generated in a shape of a ring by thermal oxidation treatment and there exists no defect region detected by Cu deposition. Thereby, there can be produced a silicon single crystal wafer according to CZ method, which does not belong to any of V region rich in vacancies, OSF region and I region rich in interstitial silicons, and can surely improve electric characteristics such as oxide dielectric breakdown voltage characteristics or the like under stable manufacture conditions.
    Type: Grant
    Filed: December 26, 2001
    Date of Patent: July 5, 2005
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Masahiro Sakurada, Takeshi Kobayashi, Tatsuo Mori, Izumi Fusegawa, Tomohiko Ohta
  • Patent number: 6896727
    Abstract: An improved method of determining the concentration of nitrogen within a wafer is provided. At least a portion of the nitrogen within the wafer is initially gettered to a gettering site. In order prevent the in-diffusion of nitrogen, a barrier layer is generally deposited upon the wafer prior to gettering the nitrogen within the wafer. The nitrogen is then measured at the gettering site. The concentration of nitrogen within the wafer is then determined based upon the measurement of nitrogen at the gettering site and the diffusion coefficient for nitrogen. In this regard, the diffusion coefficient of nitrogen permits the measurement of nitrogen at the gettering site to be translated into a measurement of the concentration of nitrogen throughout the entire wafer.
    Type: Grant
    Filed: June 28, 2002
    Date of Patent: May 24, 2005
    Assignee: SEH America, Inc.
    Inventor: Sergei V. Koveshnikov
  • Patent number: 6869478
    Abstract: A method for producing a silicon ingot having no defect over a wide range of region with stability and good reproducibility, wherein when a silicon single crystal (11) is pulled up form a silicon melt (13), the shape of a solid-liquid interface (14) which a boundary between the silicon melt (13) and the silicon single crystal (11) and the temperature distribution on the side face (11b) of a single crystal under being pulled up are appropriately controlled.
    Type: Grant
    Filed: March 19, 2001
    Date of Patent: March 22, 2005
    Assignee: Komatsu Denshi Kinzoku Kabushiki Kaisha
    Inventors: Kozo Nakamura, Toshiaki Saishoji, Shinji Togawa, Toshirou Kotooka, Susumu Maeda
  • Patent number: 6869477
    Abstract: A process for preparing a single crystal silicon in accordance with the Czochralski method, is provided. More specifically, by quickly reducing the pull rate at least once during the growth of the neck portion of the single crystal ingot, in order to change the melt/solid interface shape from a concave to a convex shape, the present process enables zero dislocation growth to be achieved in a large diameter neck within a comparably short neck length, such that large diameter ingots of substantial weight can be produced safely and at a high throughput.
    Type: Grant
    Filed: February 20, 2001
    Date of Patent: March 22, 2005
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Hiroyo Haga, Makoto Kojima, Shigemi Saga
  • Patent number: 6858076
    Abstract: There are provided a system for manufacturing a single-crystal ingot which is equipped with a cooler for cooling the single-crystal ingot being pulled and is capable of forming a tail without involvement of excessive heating of a crucible, as well as to a method for controlling the system. In a system for manufacturing a single-crystal ingot having a cooler for cooling a single-crystal ingot which is being pulled from molten raw material (called a single-crystal pulled ingot), when a tail of the single-crystal pulled ingot is formed, the cooler is moved away from the solid/melt interface between the single-crystal ingot and the molten raw material, to thereby reduce the power dissipated by the system. In the system, the cooler is moved upward after the end of a product area of the single-crystal ingot has been cooled until it passes through a grown-in defect temperature range.
    Type: Grant
    Filed: May 10, 2000
    Date of Patent: February 22, 2005
    Assignee: Komatsu Electronic Metals Co., Ltd.
    Inventors: Hirotaka Nakajima, Toshirou Kotooka, Yoshiyuki Shimanuki, Hiroshi Inagaki, Shigeki Kawashima, Makoto Kamogawa
  • Patent number: 6815605
    Abstract: There can be provided according to the present invention a silicon single crystal produced according to Czochralski method to which Ga (gallium) is added as a dopant characterized in that a resistivity is 5&OHgr;.cm to 0.1&OHgr;.cm and a method for producing a silicon single crystal to which Ga (gallium) is added as a dopant according to Czochralski method characterized in that Ga is added in a silicon melt in a crucible, a seed crystal is brought into contact with the silicon melt and is pulled with rotating to grow a silicon single crystal ingot. Thereby, a silicon single crystal and silicon single crystal wafer and a method for producing them that can produce a solar cell characterized in that photo-degradation is not caused even in the single crystal having high oxygen concentration and a conversion efficiency of optical energy is very high.
    Type: Grant
    Filed: January 18, 2001
    Date of Patent: November 9, 2004
    Assignees: Shin-Etsu Handotai Co., Ltd., Shin-Etsu Chemical Co., Ltd.
    Inventors: Takao Abe, Teruhiko Hirasawa, Katsushi Tokunaga, Tetsuya Igarashi, Masafumi Yamaguchi
  • Patent number: 6802899
    Abstract: There is provided a manufacturing process for a CZ silicon single crystal wafer which is subjected to heat treatment wherein slip resistance of a portion of the CZ silicon single crystal wafer in contact with a heat treatment boat is improved with extreme simplicity, convenience and very low cost. A silicon single crystal rod is grown by means of a Czochralski method in a condition that an OSF ring region is formed in a peripheral region of the silicon single crystal rod and the grown silicon signal crystal rod is processed into silicon single crystal wafers, whereby the silicon single crystal wafer is obtained such that when the silicon single crystal wafer is subjected to heat treatment, at least a portion of the silicon single crystal wafer in contact between the wafer and the boat is formed of an OSF ring region.
    Type: Grant
    Filed: July 9, 2001
    Date of Patent: October 12, 2004
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventor: Masaro Tamatsuka
  • Patent number: 6800132
    Abstract: A method for producing a silicon ingot through pulling up a silicon single crystal according to the Czochralski method, wherein the silicon single crystal is pulled up while being doped with nitrogen in such a condition as to form a part having a nitrogen content of 5×1013 atoms/cm3 to 1×1015 atoms/cm3. A silicon wafer having a nitrogen content of 5×1013 atoms/cm3 to 1×1015 atoms/cm3 which is suitable for being treated with heat in a non-oxidizing atmosphere is manufactured of an ingot produced by using the method. The method can be used for producing a silicon wafer being doped with nitrogen and having satisfactory characteristics for use in a semiconductor device.
    Type: Grant
    Filed: February 12, 2002
    Date of Patent: October 5, 2004
    Assignee: Komatsu Denshi Sinzoku Kabushiki
    Inventors: Satoshi Komiya, Shiro Yoshino, Masayoshi Danbata, Kouichirou Hayashida
  • Patent number: 6776840
    Abstract: A method and apparatus for controlling the diameter of a monocrystalline ingot as it is being pulled from a melt by changing the temperature of the melt. The ingot is pulled from the melt at a target rate that substantially follows a predetermined velocity profile. A temperature model represents variations in the melt temperature in response to variations in power supplied to a heater for heating the melt. In generating a temperature set point representing a target melt temperature, an error between a target diameter and a measured diameter of the ingot is determined and proportional-integral-derivative (PID) control is performed on the error signal. The PID control generates the temperature set point as a function of the error signal. In turn, the temperature model determines a power set point for the power supplied to the heater as a function of the temperature set point generated by the PID control and the power supplied to the heater is adjusted according to the power set point.
    Type: Grant
    Filed: February 10, 2000
    Date of Patent: August 17, 2004
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Robert H. Fuerhoff, Steven L. Kimbel
  • Patent number: 6767400
    Abstract: In the CZ process using a cooling member surrounding a single crystal, the cooling member is permitted to effectively serve to increase a pulling speed. Cracks of the single crystal due to excessive cooling are prevented to occur. A high crystal quality is acquired. In order to realize these objects, the temperature of the inner peripheral surface of the cooling member 6 opposing to the outer peripheral surface of the single crystal 4 is restricted to 500° C. or below, even in the lower end, the temperature of which becomes the highest. To achieve this restriction, the thickness T of the cooling member 5 is 10 to 50 mm. The height H of the cooling member 6 is 0.1 to 1.5 times the diameter D of the single crystal 4.
    Type: Grant
    Filed: September 24, 2002
    Date of Patent: July 27, 2004
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Takayuki Kubo, Fumio Kawahigashi, Hiroshi Asano, Shinichiro Miki, Manabu Nishimoto
  • Patent number: 6749683
    Abstract: A process for controlling the amount of insoluble gas trapped by a silicon melt is disclosed. Polycrystalline silicon is charged to a crucible in a crystal pulling apparatus and the apparatus sealed and evacuated. After evacuation, the crystal pulling apparatus is backfilled at least once with a gas having a high solubility in silicon, such as nitrogen. The highly soluble gas fills in cavities between the polycrystalline silicon pieces and between the pieces and the crucible such that when the silicon is melted and bubbles form in the molten silicon the bubbles will solubilize into the melt instead of becoming entrapped in the growing crystal.
    Type: Grant
    Filed: October 23, 2001
    Date of Patent: June 15, 2004
    Assignee: MEMC Electronic Materials, Inc.
    Inventor: John D. Holder
  • Patent number: 6743289
    Abstract: A thermal annealing process for producing a low defect density single crystal silicon wafer. The process includes thermally annealing a wafer having a first axially symmetric region which extends radially inwardly from the circumferential edge, contains silicon self-interstitials as the predominant intrinsic point defect and is substantially free of agglomerated interstitial defects and a second axially symmetric region which has vacancies as the predominant intrinsic point defect. The wafer is subjected to a thermal anneal at a temperature in excess of about 1000° C. in an atmosphere of hydrogen, argon or a mixture thereof to dissolve agglomerated vacancy defects present in the second axially symmetric region within a layer extending from the front side toward the central plane.
    Type: Grant
    Filed: February 11, 2002
    Date of Patent: June 1, 2004
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Robert J. Falster, Martin Jeffrey Binns, Alan Wang
  • Patent number: 6733585
    Abstract: In a Czochralski (CZ) single crystal puller equipped with a cooler and a thermal insulation member, which are to be disposed in a CZ furnace, smooth recharge and additional charge of material are made possible. Further, elimination of dislocations from a silicon seed crystal by use of the Dash's neck method can be performed smoothly. To these ends, there is provided a CZ single crystal puller, wherein a cooler and a thermal insulation member are immediately moved upward away from a melt surface during recharge or additional charge of material or during elimination of dislocations from a silicon seed crystal by use of the Dash's neck method.
    Type: Grant
    Filed: February 1, 2001
    Date of Patent: May 11, 2004
    Assignee: Komatsu Denshi Kinzoku Kabushiki Kaisha
    Inventors: Hiroshi Inagaki, Shigeki Kawashima, Makoto Kamogawa, Tadashi Hata
  • Patent number: 6726764
    Abstract: A control method for use with a crystal puller for growing a monocrystalline semiconductor crystal from a melt according to the Czochralski process. The method includes defining an initial interval of time for observing growth of the crystal being pulled from the melt and determining diameter variations occurring during the interval. Based on the variations in the crystal diameter, the method defines a function r(t). By performing a best fit routine on the function r(t), the method deduces current values of crystal radius rf, meniscus height hf and growth rate Vgf at the end of the observation interval. The method also includes determining pull rate and heater power parameters as a function of the growth rate to control the crystal puller to minimize variations in both crystal diameter and growth rate during subsequent growth of the crystal.
    Type: Grant
    Filed: November 13, 2001
    Date of Patent: April 27, 2004
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Paolo Mutti, Vladmir V. Voronknov
  • Patent number: 6676753
    Abstract: A silicon wafer is provided having controlled distribution of defects, in which denuded zones having a sufficient depth inward from the surface of the wafer are combined with a high gettering effect in a bulk region of the wafer. In the silicon wafer, oxygen precipitates, which act as intrinsic gettering sites, show vertical distribution. The oxygen precipitate concentration profile from the top to the bottom surfaces of the wafer includes first and second peaks at first and second predetermined depths from the top and bottom surfaces of the wafer, denuded zones between the top and bottom surfaces of the wafer and each of the first and second peaks, and a concave region between the first and second peaks, which corresponds to a bulk region of the wafer. For such an oxygen precipitate concentration profile, the wafer is exposed to a rapid thermal annealing process in a gas mixture atmosphere comprising ammonia (NH3) and argon (Ar) at temperatures below about 1200° C.
    Type: Grant
    Filed: September 4, 2002
    Date of Patent: January 13, 2004
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Jea-gun Park