With Liquid Flow Control Or Manipulation During Growth (e.g., Mixing, Replenishing, Magnetic Levitation, Stabilization, Convection Control, Baffle) Patents (Class 117/30)
  • Patent number: 5858084
    Abstract: A method of growing crystals from solution is described which includes growing crystals from a solution comprising ions under the combined effect of gravity and an applied magnetic field, in which the magnetic field in the range of about 1 to 10 times the strength of the Earth's magnetic field.
    Type: Grant
    Filed: February 28, 1997
    Date of Patent: January 12, 1999
    Assignee: Massachusetts Institute of Technology
    Inventors: Min-Chang Lee, Caroline H. Lee
  • Patent number: 5851283
    Abstract: A single crystal production apparatus based on an HMCZ method for production a large-diametered single crystal having a uniform microscopic oxygen concentration distribution in its crystal growth direction to thereby provide a wafer having a high in-plane uniformity of oxygen concentration distribution. In the single crystal production apparatus based on the HMCZ method, when B denotes a vertical position of the bottom surface of a melt within a crucible and L denotes the depth of the melt at the time of starting crystal pulling operation, a vertical position of the coil central axis Cc of superconducting electromagnets 12 and 15 is controlled to be a proper value included in a range from a position below the position B by {(1/3).times.L} to a position above the position B by {(1/3).times.L} to pull the single crystal.
    Type: Grant
    Filed: December 20, 1996
    Date of Patent: December 22, 1998
    Assignee: Shin-Etsu Handotai Co. Ltd.
    Inventors: Ryouji Hoshi, Masashi Sonokawa, Izumi Fusegawa, Tomohiko Ohta
  • Patent number: 5840115
    Abstract: A method of growing a single crystal of semiconductor using a CZ growth technique, having a step (0<t<t1) wherein a single crystal of semiconductor is pulled while a source material is supplied continuously to maintain a constant amount of semiconductor melt, and a step (t2<t<t3) wherein the supply of source material is halted, and the single crystal of semiconductor is pulled using residual melt from the first step.
    Type: Grant
    Filed: January 10, 1997
    Date of Patent: November 24, 1998
    Assignee: Zag Ltd.
    Inventors: Hiroaki Taguchi, Takashi Atami, Hisashi Furuya, Michio Kida
  • Patent number: 5827366
    Abstract: In a Czochralski monocrystalline silicon growing apparatus for growing a silicon monocrystalline by pulling up a crystal seed by a wire in a growing furnace, a magnetic ring is mounted on the silicon monocrystal, and an electromagnet is fixed to the growing furnace for pulling up the magnetic ring.
    Type: Grant
    Filed: November 22, 1996
    Date of Patent: October 27, 1998
    Assignee: NEC Corporation
    Inventor: Masahito Watanabe
  • Patent number: 5817176
    Abstract: The present invention relates to an apparatus for preparing a single crystal of silicon by which a high-quality single crystal of silicon can be prepared by changing the rotation rate of a crucible or a seed and a process for preparing a single crystal of silicon thereby. As compared with a conventional apparatus employing Czochralski method, which comprises a rotating axis of seed, a seed, a crucible, a heater, a rotary axis of crucible, a chamber and an adiabatic layer, the apparatus of the present invention is characterized by the improvement comprising means for controlling the rotation rate of the crucible or the seed, each of which consists of a D.C. voltage, a function generator, a voltage summing circuit and a stepping motor.
    Type: Grant
    Filed: April 17, 1996
    Date of Patent: October 6, 1998
    Assignee: Korea Advanced Institute of Science and Technology
    Inventors: Hyung-Jin Sung, Jung-Il Choi
  • Patent number: 5797990
    Abstract: Orbital oscillations of the crystal ingot suspended in a cable in a Czochralski crystal puller are damped by mechanically connecting a high-temperature conductor to the ingot and generating a magnetic field in the vicinity of the conductor. The magnetic field induces an eddy current in the conductor when the ingot moves. The eddy current then interacts with the magnetic field to damp motion of the ingot. In one embodiment, the magnetic field generator is moved as the ingot grows to maintain the magnetic field in the vicinity of the conductor. In another embodiment, the strength of the magnetic field is adjusted dependent on the amplitude of the oscillations to conserve power.
    Type: Grant
    Filed: February 26, 1996
    Date of Patent: August 25, 1998
    Assignee: Ferrofluidics Corporation
    Inventor: Zhixin Li
  • Patent number: 5795383
    Abstract: A method and a mechanism for lifting a gas flow-guide cylinder of a crystal pulling apparatus are disclosed. The crystal pulling apparatus includes a crucible for accommodating a crystalline material and for melting the crystalline material through heating, and a gas flow-guide cylinder capable of being moved upward/downward above the crucible. The crystal pulling apparatus is operated to grow a single crystal from the crystalline material by a pulling method. When a solid crystalline material is to be placed in the crucible, the gas flow-guide cylinder is moved upward to thereby separate the bottom end of the gas flow-guide cylinder away from the top portion of the crucible. This prevents the crystalline material from coming into contact with the gas flow-guide cylinder.
    Type: Grant
    Filed: December 5, 1996
    Date of Patent: August 18, 1998
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Hideo Okamoto, Toshiharu Uesugi, Atsushi Iwasaki, Tetsuhiro Oda
  • Patent number: 5792255
    Abstract: In a single crystal manufacturing method by a horizontal magnetic field applied CZ method wherein coils are disposed interposing a crucible coaxially with each other, the coils constituting superconductive electromagnets of a magnetic field application apparatus and the silicon crystal is pulled from melt in the crucible while applying a horizontal magnetic field to the melt; an elavation apparatus capable of finely adjusting relative positions of the superconductive electromagnets and the crcucible in a vertical direction is disposed. The descent of a central portion Cm in a depth direction of the melt is canceled by elevating the crucible with the elevating apparatus, the descent being accompanied with proceeding of process of pulling the single crystal, thereby a coil central axis Cc of the superconductive electromagnets always passes through the central portion Cm or below this portion.
    Type: Grant
    Filed: May 30, 1996
    Date of Patent: August 11, 1998
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Eiichi Iino, Kiyotaka Takano, Masanori Kimura, Hirotoshi Yamagishi
  • Patent number: 5785752
    Abstract: Proposed is an improvement in the method for the preparation of a chip of an oxide garnet film epitaxially having a specific chemical composition as grown on the surface of a GGG substrate wafer having a crystallographic plane orientation of (111), which is useful as a working element in a magnetostatic wave device such as high-frequency filters, signal noise enhancers, isolators and the like with decreased temperature dependence of the properties. The epitaxially grown single crystal film is adjusted to have such dimensions that the thickness h and the smallest dimension L within the plane of the film satisfy the relationship that the ratio h/L is in the range from 0.001 to 0.25.
    Type: Grant
    Filed: December 12, 1995
    Date of Patent: July 28, 1998
    Assignee: Shin-Etsu Chemical Co., Ltd.
    Inventors: Masayuki Tanno, Toshihiko Ryuo
  • Patent number: 5733368
    Abstract: In a method of manufacturing a silicon monocrystal using a continuous Czochralski method, a silicon monocrystal is pulled from a silicon melt in a crucible while a silicon material is fed to the crucible. Supply of the silicon material is suspended until the temperature distribution of the silicon melt becomes stable after initiation of a straight body forming process, and the supply of the silicon material is commenced when the temperature distribution of the silicon melt has become stable. The feed rate of the silicon material is gradually increased until the feed rate becomes equal to a solidification rate of the silicon melt after the supply of the silicon material has been commenced. This method prevents the silicon monocrystal from becoming a polycrystal during the manufacture thereof.
    Type: Grant
    Filed: February 20, 1997
    Date of Patent: March 31, 1998
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Naoki Nagai, Isamu Harada, Michiaki Oda
  • Patent number: 5725661
    Abstract: An equipment for producing silicon single crystals based on an MCZ method, which enables an operator to be protected from dangerous exposure to magnetic field without involving increase in the size of the silicon single crystal production equipment. In the silicon single crystal production equipment based on the MCZ method, a growth furnace control apparatus for control of a pulling apparatus is located away from the pulling apparatus by a predetermined distance so that the intensity of magnetic field immediately close to the growth furnace control apparatus can become 300 gausses or less. A monitoring camera for observing the growing condition of the silicon single crystal is mounted to a window 5a of a growth furnace to be operatively connected to a monitor of the growth furnace control apparatus and to cause the growth furnace control apparatus to control the pulling apparatus on a remote control basis.
    Type: Grant
    Filed: July 1, 1996
    Date of Patent: March 10, 1998
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Izumi Fusegawa, Toshiro Hayashi, Tomohiko Ohta, Masayuki Arai
  • Patent number: 5704974
    Abstract: When a Si single crystal 8 is pulled up from a melt 6 received in a crucible 2, the state of eddy flows generated in the melt 6 is judged from the temperature distribution of the melt at the surface. According to the result of judgement, the gas, i.e. N.sub.2, Xe or Kr, which causes extraoridnary deviation in the density of a melt 6 is added to an atmospheric gas, so as to keep the eddy flows under unstabilized condition. The effect of said gas is typical in the case of crystal growth from the melt to which a dopant such as Ca, Sb, Al, As or In having the effect to suppress the extraordinary deviation in the density is added. Since the single crystal is pulled up from the melt held in the temperature-controlled condition at the surface, impurity distribution and oxygen distribution are made uniform along the direction of crystal growth. A single crystal obtained in this way has highly-stabilized quality.
    Type: Grant
    Filed: March 22, 1996
    Date of Patent: January 6, 1998
    Assignees: Research Development Corporation of Japan, Sumitomo Sitix Corporation, Toshiba Ceramics Co., Ltd., Nippon Steel Corporation, Komatsu Electronic Metals Co., Ltd., Mitsubishi Materials Corporation
    Inventors: Koji Izunome, Souroku Kawanishi, Shinji Togawa, Atsushi Ikari, Hitoshi Sasaki, Shigeyuki Kimura
  • Patent number: 5690734
    Abstract: A process is disclosed for continuously producing a single crystal by drawing downwardly a melt of a single crystal raw material, wherein a single crystal body grown from the melt is continuously pulled downwardly, and a plurality of single crystal products are continuously formed by intermittently cutting the single crystal body being downwardly moved.
    Type: Grant
    Filed: March 19, 1996
    Date of Patent: November 25, 1997
    Assignee: NGK Insulators, Ltd.
    Inventors: Minoru Imaeda, Akihiko Honda, Katsuhiro Imai, Yuichiro Imanishi, Nobuyuki Kokune, Shoji Sogo, Kazuaki Yamaguchi, Tetsuo Taniuchi
  • Patent number: 5690731
    Abstract: A method of growing a crack-free single crystal is disclosed which comprises heating raw materials in a crucible to thereby obtain a melt of the raw materials, contacting a lower end of a seed crystal with the melt and pulling the seed crystal to thereby grow a single crystal, and wherein the melt of the crucible flows from its surface toward its inner part inside the crucible by convection at a position locating outside a region where the growth of the single crystal occurs. This flow control can be achieved by, for example, surrounding the crucible with a heat insulation refractory composed of a pair of semicylindrical refractories disposed so as to provide a circular cross section with differently sized gaps. In the above-mentioned method, the seed crystal may be rotated during a shoulder growth in which the single crystal has its diameter increased from that of the seed crystal to a target diameter at a rotation rate greater than that during a subsequent cylindrical body growth.
    Type: Grant
    Filed: March 30, 1995
    Date of Patent: November 25, 1997
    Assignee: Hitachi Chemical Company Ltd.
    Inventors: Yasushi Kurata, Kazuhisa Kurashige, Hiroyuki Ishibashi
  • Patent number: 5683504
    Abstract: When a single crystal is pulled up from a melt, the difference .DELTA.T between temperatures at the bottom of a crucible and at the interface of crystal growth is controlled so as to hold the Rayleigh constant defined by the formula of:R a=g.multidot..beta..multidot..DELTA.T.multidot.L/.kappa..multidot..nu.within the range of 5.times.10.sup.5 -4.times.10.sup.7, wherein g represents the acceleration of gravity, .beta. the volumetric expansion coefficient of the melt, L the depth of the melt, .kappa. thermal diffusivity and .nu. the kinematic viscocity. Since the convection mode of the melt at the interface of crystal growth is constantly held in the region of soft turbulence, a single crystal is grown under the stabilized temperature condition without the transfer of the impurity distribution in the melt into the growing single crystal.
    Type: Grant
    Filed: March 22, 1996
    Date of Patent: November 4, 1997
    Assignees: Research Development Corporation of Japan, Sumitomo Sitix Corporation, Toshiba Ceramics Co., Ltd., Nippon Steel Corporation, Komatsu Electronic Metals Co., Ltd., Mitsubishi Materials Corporation
    Inventors: Koji Izunome, Souroku Kawanishi, Shinji Togawa, Atsushi Ikari, Hitoshi Sasaki, Shigeyuki Kimura
  • Patent number: 5524571
    Abstract: Herein disclosed are apparatuses for manufacturing compound semiconductor polycrystals comprising a pressure vessel, an upper shaft, a container for a first component fixed to the upper shaft, a heater around the container, a lower shaft, a susceptor and a crucible for charging a second component, a heater for the crucible and a communicating pipe for spatially connecting the container and the crucible optionally provided with a porous member at the lower extremity and/or a cylindrical member for confining a space over a part of the melt surface contained in the crucible from the remaining inner space of the vessel, the apparatuses permitting the substantial reduction of the reaction time and an improvement of the yield of the polycrystals due to the presence of the porous member and/or the cylindrical member separating the inner space of the vessel into two portions.
    Type: Grant
    Filed: February 9, 1990
    Date of Patent: June 11, 1996
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Akihisa Kawasaki, Toshihiro Kotani
  • Patent number: 5492079
    Abstract: The process includes processing a molten phase of semiconductor material ering a solid phase of the material and having a free surface opposite this solid phase, into which, during the crystallization procedure, energy is radiated and material is fed in in granular form, which material floats and is melted. As a result, at the opposite solid/liquid interface, material grows on the solid phase which is drawn downwards in accordance with the growth rate. The process allows mono- or polycrystalline rods or blocks to be obtained. The main advantages of the process are that it can be carried out without melting vessels, it is possible to use granular material, and the energy balance is favorable because of the small amounts of melt.
    Type: Grant
    Filed: July 5, 1994
    Date of Patent: February 20, 1996
    Assignee: Wacker-Chemitronic Gesellschaft fur Elektronik-Grundstoffe mbH
    Inventors: Joachim Geissler, Ulrich Angres
  • Patent number: 5450814
    Abstract: A plurality of shield blades 31 for defining an opening 25 surrounding a single crystal 15 are provided between a melt 14 received in a crucible 10 and a screen 30. The shield blades 21 are carried by operation rods 23 so as to make the gap between the inner edges of the shield blades 23 and the surface of the single crystal 15 constant. Since crystal growth continues under the same condition from the beginning to the end, an obtained single crystal 15 is free from defects such as dislocations and excellent in homogenieity.
    Type: Grant
    Filed: October 14, 1993
    Date of Patent: September 19, 1995
    Assignees: Research Development Corporation of Japan, Yutaka Shiraishi, Kazutaka Terashima
    Inventors: Yutaka Shiraishi, Kazutaka Terashima
  • Patent number: 5437242
    Abstract: A process and an apparatus for carrying out the process provides for the accurate and simple control of the melt level when pulling single crystals according to the Czochralski process. The process comprises disposing a mechanical reference mark above the melt in such a way that it causes a reflection from the melt surface. An image of the metal surface is then recorded, and with the aid of the recorded image the distance of the mechanical reference mark from the melt surface is determined. An actual signal proportional to this distance is then generated and is compared with a set point signal, and the melt level is changed as a function of any difference observed.
    Type: Grant
    Filed: August 18, 1993
    Date of Patent: August 1, 1995
    Assignee: Wacker-Chemitronic Gessellschaft fuer Elektronik-Grundstoffe mbH
    Inventors: Christian Hofstetter, Walter Berger, Werner Bauer, Bernd Mittelbach
  • Patent number: 5363796
    Abstract: An apparatus for growing a single crystal having a crucible, two heaters arranged at the outside of the crucible and along the vertical direction, a heat shield placed at the outside of the heaters, a radiation shield for shielding the single crystal from the radiation heat, and an upper heat shield for preventing the upward heat, transfer of the heaters. In the apparatus, a melted layer and solid layer of raw material are formed in the upper and lower portions of the crucible, respectively. While melting the solid layer, the single crystal is pulled up. The lower portion of the heat shield is thinner than the upper portion. The ratio of the height to the diameter of the crucible is 0.85 or more. The melting amount of the solid layer is controlled in the pulling process according to the non-segregation condition in the variable-thickness melted layer method.
    Type: Grant
    Filed: February 18, 1992
    Date of Patent: November 15, 1994
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventors: Sumio Kobayashi, Shunji Miyahara, Toshiyuki Fujiwara, Takayuki Kubo, Hideki Fujiwara, Shuichi Inami