Comprising A Silicon Crystal With Oxygen Containing Impurity Patents (Class 117/20)
  • Patent number: 8216361
    Abstract: Monocrystalline semiconductor wafers have defect-reduced regions, the defect-reduced regions having a density of GOI-relevant defects within the range of 0/cm2 to 0.1/cm2 and occupy overall an areal proportion of 10% to 100% of the planar area of the semiconductor wafer, wherein the remaining regions of the semiconductor wafer have a significantly higher defect density than the defect-reduced regions. The wafers may be produced by a method for annealing GOI relevant defects in the wafer, by irradiating defined regions of a side of the semiconductor wafer by laser wherein each location is irradiated with a power density of 1 GW/m2 to 10 GW/m2 for at least 25 ms, wherein the laser emits radiation of a wavelength above the absorption edge of the wafer semiconductor material and wherein the temperature of the wafer rises by less than 20 K as a result of irradiation.
    Type: Grant
    Filed: September 7, 2011
    Date of Patent: July 10, 2012
    Assignee: Siltronic AG
    Inventors: Dieter Knerer, Andreas Huber, Ulrich Lambert, Friedrich Passek
  • Patent number: 8216362
    Abstract: Processes for preparing a single crystal silicon ingot are disclosed. In certain embodiments, the processes involve controlling (1) a growth velocity, v, of the ingot as well as (2) an average axial temperature gradient, G, a corrected average axial temperature gradient, Gcorrected, or an effective average axial temperature gradient, Geffective, during the growth of at least a segment of the constant diameter portion of the ingot.
    Type: Grant
    Filed: May 18, 2007
    Date of Patent: July 10, 2012
    Assignee: MEMC Electronic Materials, Inc.
    Inventor: Milind S. Kulkarni
  • Patent number: 8197594
    Abstract: Silicon wafers having a density of BMDs with sizes between 20 to 40 nm at positions ?20 ?m below the wafer surface in the range of 5×1011/cm3, and a density of BMDs with sizes of ?300 nm?1×107/cm3, exhibit reduced slip dislocation and warpage. The wafers are sliced from a crystal grown under specific conditions and then subjected to both low temperature heat-treatment and high temperature anneal.
    Type: Grant
    Filed: September 19, 2007
    Date of Patent: June 12, 2012
    Assignee: Siltronic AG
    Inventors: Katsuhiko Nakai, Wilfried von Ammon, Sei Fukushima, Herbert Schmidt, Martin Weber
  • Publication number: 20120126171
    Abstract: A method of growing a rare-earth oxyorthosilicate crystal, and crystals grown using the method are disclosed. The method includes preparing a melt by melting a first substance including at least one first rare-earth element and providing an atmosphere that includes an inert gas and a gas including oxygen.
    Type: Application
    Filed: November 24, 2010
    Publication date: May 24, 2012
    Applicant: SIEMENS MEDICAL SOLUTIONS USA, INC.
    Inventors: Mark S. Andreaco, Piotr Szupryczynski, A. Andrew Carey
  • Patent number: 8177910
    Abstract: To reduce the heat input to the bottom of the crucible and to control heat extraction independently of heat input, a shield can be raised between a heating element and a crucible at a controlled speed as the crystal grows. Other steps could include moving the crucible, but this process can avoid having to move the crucible. A temperature gradient is produced by shielding only a portion of the heating element; for example, the bottom portion of a cylindrical element can be shielded to cause heat transfer to be less in the bottom of the crucible than at the top, thereby causing a stabilizing temperature gradient in the crucible.
    Type: Grant
    Filed: March 1, 2011
    Date of Patent: May 15, 2012
    Assignee: GT Crystal Systems, LLC
    Inventors: Frederick Schmid, Chandra P. Khattak, David B. Joyce
  • Patent number: 8142565
    Abstract: A vitreous silica crucible for pulling single-crystal silicon, which is formed of vitreous silica and has a bottomed cylindrical shape, wherein, in a liquid-level movement range in the inner surface of the crucible, ranging from a position corresponding to the liquid surface level of a silicon melt at the time of stating the pulling of single-crystal silicon to a position corresponding to the liquid surface level of a silicon melt at the time of finishing the pulling of single-crystal silicon, the concentration of an OH group included in the vitreous silica is higher in an erosion thickness portion of the inner surface of the crucible than that in the range lower than the liquid surface level which is positioned below the liquid-level movement range.
    Type: Grant
    Filed: November 28, 2008
    Date of Patent: March 27, 2012
    Assignee: Japan Super Quartz Corporation
    Inventors: Hiroshi Kishi, Minoru Kanda
  • Patent number: 8110042
    Abstract: Using a pulling-up apparatus, an oxygen concentration of the monocrystal at a predetermined position in a pulling-up direction is controlled based on a relationship in which the oxygen concentration of the monocrystal is decreased as a flow rate of the inactive gas at a position directly above a free surface of the dopant-added melt is increased when the monocrystal is manufactured with a gas flow volume in the chamber being in the range of 40 L/min to 400 L/min and an inner pressure in the chamber being in the range of 5332 Pa to 79980 Pa. Based on the relationship, oxygen concentration is elevated to manufacture the monocrystal having a desirable oxygen concentration. Because the oxygen concentration is controlled under a condition corresponding to a condition where the gas flow rate is rather slow, the difference between a desirable oxygen concentration profile of the monocrystal and an actual oxygen concentration profile is reduced.
    Type: Grant
    Filed: May 7, 2008
    Date of Patent: February 7, 2012
    Assignee: Sumco Techxiv Corporation
    Inventors: Yasuhito Narushima, Shinichi Kawazoe, Fukuo Ogawa, Tsuneaki Tomonaga, Yasuyuki Ohta, Toshimichi Kubota, Shinsuke Nishihara
  • Patent number: 8105436
    Abstract: A single crystal silicon wafer for use in the production of insulated gate bipolar transistors is made of single crystal silicon grown by the Czochralski method and has a gate oxide with a film thickness of from 50 to 150 nm. The wafer has an interstitial oxygen concentration of at most 7.0×1017 atoms/cm3, a resistivity variation within the plane of the wafer of at most 5% and, letting tox (cm) be the gate oxide film thickness and S (cm2) be the electrode surface area when determining the TZDB pass ratio, a density d (cm?3) of crystal originated particles (COP) having a size at least twice the gate oxide film thickness which satisfies the formula d??ln(0.9)/(S·tox/2). The wafers have an increased production yield and a small resistivity variation.
    Type: Grant
    Filed: September 22, 2008
    Date of Patent: January 31, 2012
    Assignee: Sumco Corporation
    Inventor: Shigeru Umeno
  • Patent number: 8088219
    Abstract: Monocrystalline semiconductor wafers have defect-reduced regions, the defect-reduced regions having a density of GOI-relevant defects within the range of 0/cm2 to 0.1/cm2 and occupy overall an areal proportion of 10% to 100% of the planar area of the semiconductor wafer, wherein the remaining regions of the semiconductor wafer have a significantly higher defect density than the defect-reduced regions. The wafers may be produced by a method for annealing GOI relevant defects in the wafer, by irradiating defined regions of a side of the semiconductor wafer by laser wherein each location is irradiated with a power density of 1 GW/m2 to 10 GW/m2 for at least 25 ms, wherein the laser emits radiation of a wavelength above the absorption edge of the wafer semiconductor material and wherein the temperature of the wafer rises by less than 20 K as a result of irradiation.
    Type: Grant
    Filed: July 26, 2007
    Date of Patent: January 3, 2012
    Assignee: Siltronic AG
    Inventors: Dieter Knerer, Andreas Huber, Ulrich Lambert, Friedrich Passek
  • Patent number: 8043427
    Abstract: Semiconductor wafers of silicon are produced by pulling a single crystal growing on a phase boundary from a melt contained in a crucible and cutting of semiconductor wafers therefrom, wherein during pulling of the single crystal, heat is delivered to a center of the phase boundary and a radial profile of a ratio V/G from the center to an edge of the phase boundary is controlled, G being the temperature gradient perpendicular to the phase boundary and V being the pull rate. The radial profile of the ratio V/G is controlled so that the effect of thermomechanical stress in the single crystal adjoining the phase boundary, is compensated with respect to creation of intrinsic point defects. The invention also relates to defect-free semiconductor wafers of silicon, which can be produced economically by this method.
    Type: Grant
    Filed: January 29, 2008
    Date of Patent: October 25, 2011
    Assignee: Siltronic AG
    Inventors: Andreas Sattler, Wilfried von Ammon, Martin Weber, Walter Haeckl, Herbert Schmidt
  • Patent number: 7972438
    Abstract: This invention is related to material for use as an ultraviolet (UV) optical element and particularly for use as a 193 nm immersion lens element. The material for use as a UV optical element includes a Lithium Magnesium Aluminate (LMAO) body. The specific compound for this application is the disordered lithium magnesium spinel, having the general composition of LixMg2(1?x)Al4+xO8 where x=0 to 1 as the high-index UV transparent material for immersion lithography. The LMAO body may include a disordered spinel, such as, for example, a single crystal that may be cubic in symmetry, optically isotropic, and having cation disorder within the structure to reduce the intrinsic birefringence (IBR). The LMAO body has certain desired material properties and may be readily made in relatively large sizes suitable for use as the UV optical element for photolithography.
    Type: Grant
    Filed: August 29, 2007
    Date of Patent: July 5, 2011
    Assignee: Crystal Photonics, Incorporated
    Inventors: Yi-Ting Fei, Shen Jen, Bruce Chai
  • Patent number: 7918934
    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: November 29, 2006
    Date of Patent: April 5, 2011
    Assignee: Sumco Techxiv Corporation
    Inventors: Yutaka Shiraishi, Jyunsuke Tomioka, Takuji Okumura, Tadayuki Hanamoto, Takehiro Komatsu, Shigeo Morimoto
  • Patent number: 7906443
    Abstract: A wafer processing method is provided that includes the steps of heating a silicon wafer containing oxygen and irradiating an infrared ray having a wavelength within a range of 7-25 ?m on the silicon wafer, and controlling formation of oxygen precipitates within the silicon wafer by selectively setting a heating temperature for heating the silicon wafer and an irradiation intensity of the infrared ray.
    Type: Grant
    Filed: May 26, 2006
    Date of Patent: March 15, 2011
    Assignee: Fujitsu Limited
    Inventors: Katsuto Tanahashi, Hiroshi Kaneta
  • Patent number: 7875116
    Abstract: A method in which SSDs are reliably reduced while reducing void defects other than the SSDs on a wafer surface, which is essential for an annealed wafer, and ensuring that BMDs serving as gettering source in a bulk are generated, in order to stabilize the quality of the annealed wafer. Considering that annealing a silicon wafer leads to an increase of density (quantity) of deposits associated with oxygen and nitrogen and forming a core of the SSDs, SSDs are decreased by reducing the density (quantity) of the deposits associated with oxygen and nitrogen by controlling three parameters of oxygen concentration, nitrogen concentration and cooling concentration during the process of pulling and growing the silicon single crystal 6 before annealing. Alternatively, SSD is reduced by polishing after annealing.
    Type: Grant
    Filed: February 14, 2006
    Date of Patent: January 25, 2011
    Assignee: Sumco Techxiv Corporation
    Inventors: Shinya Sadohara, Ryota Suewaka, Shiro Yoshino, Kozo Nakamura, Yutaka Shiraishi, Syunji Nonaka
  • Patent number: 7862656
    Abstract: An apparatus and method is provided for pulling a crystal seed from melt for growing a single crystal. The method includes the steps of providing a crucible and providing within the crucible an outer container, and providing coaxially within the outer container an inner container. A protruding portion of the inner container protrudes downward relative to the outer container for containing melt, the inner and outer containers defining an annular channel therebetween which has a bottom wall and contains introduced charge feed. The method further includes the steps of providing for allowing fluid communication between the annular channel and the inner container, delivering charge feed into the annular channel, and generating heat from within the annular channel for preventing the formation of a condensate of the charge feed within the annular channel.
    Type: Grant
    Filed: July 3, 2007
    Date of Patent: January 4, 2011
    Assignee: Siemens Medical Solutions USA, Inc.
    Inventors: Olexy V. Radkevich, Mehmed Becirovic, Keith Ritter
  • Patent number: 7846252
    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: October 24, 2007
    Date of Patent: December 7, 2010
    Assignee: Sumco Corporation
    Inventors: Shigeru Umeno, Yasuhiro Oura, Koji Kato
  • Patent number: 7842133
    Abstract: In a method of growing a single crystal by melting a raw material within a vessel under a nitrogenous and non-oxidizing atmosphere, the vessel is oscillated and the melted raw material is contacted with an agitation medium made of a solid unreactive with the melted raw material.
    Type: Grant
    Filed: August 12, 2008
    Date of Patent: November 30, 2010
    Assignees: NGK Insulators, Ltd., Osaka University, Toyoda Gosei Co., Ltd.
    Inventors: Makoto Iwai, Takanao Shimodaira, Shuhei Higashihara, Takatomo Sasaki, Yusuke Mori, Fumio Kawamura, Shiro Yamasaki, Koji Hirata
  • Publication number: 20100294999
    Abstract: The sublimation speed of dopant can be precisely controlled without being influenced by a change over time of intra-furnace thermal environment. A dopant supply unit equipped with an accommodation chamber and a supply tube is provided. A sublimable dopant is accommodated. Upon sublimation of the dopant within the accommodation chamber, the sublimed dopant is introduced into a melt. The dopant within the accommodation chamber of the dopant supply unit is heated. The amount of heating by means of heating means is controlled so as to sublime the dopant at a desired sublimation speed. The dopant is supplied to the melt so that the dopant concentration until the first half of a straight body portion of the silicon single crystal is in the state of low concentration or non-addition.
    Type: Application
    Filed: April 23, 2008
    Publication date: November 25, 2010
    Applicant: SUMCO TECHXIV CORPORATION
    Inventors: Yasuhito Narushima, Shinichi Kawazoe, Fukuo Ogawa, Masahiro Irokawa, Toshimichi Kubota
  • Patent number: 7837791
    Abstract: A silicon single crystal wafer for a particle monitor is presented, which wafer has an extremely small amount in the surface density of light point defects and is capable of still maintaining a small surface density even after repeating the SC-1. The wafer is prepared by slicing a silicon single crystal ingot including an area in which crystal originated particles are generated, and the surface density of particles having a size of not less than 0.12 mum is not more than 15 counts/cm2 after repeating the SC-1. More preferably, a silicon single crystal wafer having a nitrogen concentration of 1×1013 1×1015 atoms/cm3 provides a surface density of not more than 1 counts/cm2 for the particles having a diameter of not less than 0.12 mum even after repeating the SC-1. Hence, a high quality wafer optimally used for a particle monitor can be obtained and a very small number of defects in the wafer make it possible to produce devices.
    Type: Grant
    Filed: May 23, 2008
    Date of Patent: November 23, 2010
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Hiroki Murakami, Masahiko Okui, Hiroshi Asano
  • Patent number: 7803228
    Abstract: By using oxygen-containing silicon wafers obtained by the CZ method and by combining the first heat treatment comprising controlled heat-up operation (ramping) with the second heat treatment comprising high-temperature heat treatment and medium temperature heat treatment in accordance with the process for producing high-resistance silicon wafers according to the present invention, it is possible to obtain high-resistance silicon wafers capable of maintaining their high resistance even after heat treatment in the process of device manufacture while efficiently inhibiting the formation of oxygen donors and preventing changes in resistivity. Further, excellent epitaxial wafers and SOI wafers can be produced using those high-resistance silicon wafers and, therefore, they can be applied in a wide field including high-frequency communication devices and analog/digital hybrid devices, among others.
    Type: Grant
    Filed: August 2, 2004
    Date of Patent: September 28, 2010
    Assignee: Sumco Corporation
    Inventors: Kazunari Kurita, Shinsuke Sadamitsu, Hiroyuki Takao, Masataka Hourai
  • Patent number: 7799130
    Abstract: A silicon single crystal ingot growing apparatus for growing a silicon single crystal ingot based on a Czochralski method The silicon single crystal ingot growing apparatus includes a chamber; a crucible provided in the chamber, and for containing a silicon melt; a heater provided at the outside of the crucible and for heating the silicon melt; a pulling unit for ascending a silicon single crystal grown from the silicon melt; and a plurality of magnetic members provided at the outside of the chamber and for asymmetrically applying a magnetic field to the silicon melt Such a structure can uniformly controls an oxygen concentration at a rear portion of a silicon single crystal ingot using asymmetric upper/lower magnetic fields without replacing a hot zone In addition, such a structure can controls a flower phenomenon generated on the growth of the single crystal by the asymmetric magnetic fields without a loss such as the additional hot zone (H/Z) replacement, P/S down, and SR variance.
    Type: Grant
    Filed: July 27, 2006
    Date of Patent: September 21, 2010
    Assignee: Siltron, Inc.
    Inventors: Young Ho Hong, Man Seok Kwak, Ill-Soo Choi, Hyon-Jong Cho, Hong Woo Lee
  • Publication number: 20100164071
    Abstract: Silicon wafers having excellent voltage resistance characteristics of an oxide film and high C-mode characteristics are derived from single crystal silicon ingots doped with nitrogen and hydrogen, characterized in that a plurality of voids constituting a bubble-like void aggregates are present ?50% relative to total voids; a V1 region having a void density of over 2×104/cm3 and below 1×105/cm3 is ?20% of the total area of wafer; a V2 region having a void density of 5×102 to 2×104/cm3 occupies ?80% of the total area of the wafer; and bulk microdefect density is ?5×108/cm3.
    Type: Application
    Filed: December 16, 2009
    Publication date: July 1, 2010
    Applicant: Siltronic AG
    Inventors: Katsuhiko Nakai, Atsushi Ikari, Masamichi Ohkubo
  • Patent number: 7740702
    Abstract: A silicon wafer and a method for manufacturing the same are provided, wherein the silicon wafer has no crystal defects in the vicinity of the surface and provides excellent gettering efficiency in the process of manufacturing devices without IG treatment. The oxygen concentration and the carbon concentration are controlled respectively within a range of 11×1017-17×1017 atoms/cm3 (OLD ASTM) and within a range of 1×1016-15×1016 atoms/cm3 (NEW ASTM). A denuded zone having no crystal defects due to the existence of oxygen is formed on the surface and in the vicinity thereof, and oxygen precipitates are formed at a density of 1×104-5×106 counts/cm2, when a heat treatment is carried out at a temperature of 500-1000° C. for 1 to 24 hours. In the method for manufacturing the silicon wafer, moreover, the silicon wafer having the oxygen and carbon concentrations as controlled above is heat-treated at a temperature of 1100° C.-1380° C. for 1 to 10 hours.
    Type: Grant
    Filed: December 22, 2006
    Date of Patent: June 22, 2010
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventor: Yasuo Koike
  • Patent number: 7708831
    Abstract: A method for producing a ZnO single crystal by a liquid phase growth technique, comprising the steps of: mixing and melting ZnO as a solute and PbF2 and PbO as solvents; and putting a seed crystal or substrate into direct contact with the obtained melted solution, thereby growing a ZnO single crystal on the seed crystal or substrate.
    Type: Grant
    Filed: February 28, 2007
    Date of Patent: May 4, 2010
    Assignee: Mitsubishi Gas Chemical Company, Inc.
    Inventors: Hideyuki Sekiwa, Jun Kobayashi, Miyuki Miyamoto
  • Patent number: 7641736
    Abstract: A method of manufacturing an SiC single crystal wafer according to the present invention includes the steps of: (a) preparing an SiC single crystal wafer 10 with a mirror-polished surface; (b) oxidizing the surface of the SiC single crystal wafer 10 with plasma, thereby forming an oxide layer 12 on the surface of the SiC single crystal wafer; and (c) removing at least a portion of the oxide layer 12 by a reactive ion etching process. Preferably, the surface of the wafer is planarized by repeatedly performing the steps (b) and (c) a number of times.
    Type: Grant
    Filed: February 22, 2005
    Date of Patent: January 5, 2010
    Assignee: Hitachi Metals, Ltd.
    Inventor: Taisuke Hirooka
  • Patent number: 7641734
    Abstract: A method of growing silicon single crystals with a [110] crystallographic axis orientation by the Czochralski method is provided according to which a silicon seed crystal doped with a high concentration of boron is used and an included angle of a conical part during shoulder section formation is maintained within a specified range. It is thereby possible to grow large-diameter and heavy-weight dislocation-free silicon single crystals with a diameter of 300 mm or more in a stable manner, without the fear of dropping the single crystal during pulling up. Therefore, the method can be properly utilized in producing silicon single crystals as semiconductor materials.
    Type: Grant
    Filed: April 2, 2008
    Date of Patent: January 5, 2010
    Assignee: Sumco Corporation
    Inventor: Shuichi Inami
  • Patent number: 7632349
    Abstract: There is provided a silicon wafer surface defect evaluation method capable of readily detecting a region where small crystal defects exist, the evaluation method comprising: a rapid heat treatment step of a silicon wafer from a silicon single-crystal ingot in an atmosphere which can nitride silicon at a temperature elevating speed of 10 to 150° C./second from a room temperature to temperatures between not lower than 1170° C. and less than a silicon melting point, holding the silicon wafer at the processing temperature for 1 to 120 seconds and then cooling the silicon wafer to the room temperature at a temperature lowering speed of 10 to 100° C./second; and a step of using a surface photo voltage method to calculate a minority carrier diffusion length on the wafer surface, thereby detecting a region on the wafer surface in which small COP's which cannot be detected at least by a particle counter exist.
    Type: Grant
    Filed: August 25, 2006
    Date of Patent: December 15, 2009
    Assignee: Sumco Corporation
    Inventors: Wataru Itou, Takeshi Hasegawa, Takaaki Shiota
  • Patent number: 7628854
    Abstract: A process for producing a silicon single crystal includes the steps of bringing a seed crystal into contact with a silicon melt, gradually pulling the seed crystal from the melt so as to form a neck having a tapered portion and a constant diameter portion, then pulling a silicon single crystal. The atmosphere used during neck formation is a hydrogen-containing atmosphere prepared by adding a hydrogen-containing substance to an inert gas. The hydrogen-containing substance has a hydrogen gas equivalent concentration in the hydrogen-containing atmosphere of 3 to 20%.
    Type: Grant
    Filed: July 14, 2006
    Date of Patent: December 8, 2009
    Assignee: Sumco Corporation
    Inventors: Toshiaki Ono, Wataru Sugimura, Takayuki Kubo, Akira Higuchi, Ken Nakajima
  • Publication number: 20090297426
    Abstract: When a monocrystal is pulled up, an additive element such as boron is added to a molten silicon, and a pulling-up condition is such that a solid solution oxygen concentration is equal to or higher than 2×1018 atoms/cm3 and a chemical compound precipitation area of silicon and the additive element is formed.
    Type: Application
    Filed: June 1, 2009
    Publication date: December 3, 2009
    Applicant: SUMCO CORPORATION
    Inventors: Takeo KATOH, Kazushige TAKAISHI
  • Patent number: 7621996
    Abstract: A method for producing a silicon wafer that has a carbon concentration of 5×1015 to 5×1017 atoms/cm3, interstitial oxygen concentration of 6.5×1017 to 13.5×1017 atoms/cm3, and a resistivity of 100 ?cm or more.
    Type: Grant
    Filed: August 29, 2008
    Date of Patent: November 24, 2009
    Assignee: Sumco Corporation
    Inventor: Kazunari Kurita
  • Patent number: 7594966
    Abstract: A method for producing a single crystal by pulling a single crystal from a raw material melt in a chamber according to the Czochralski method, including pulling a single crystal having a defect-free region, which is outside an OSF region, to occur in a ring shape in the radial direction, and in which interstitial-type and vacancy-type defects do not exist. The pulling of the single crystal is controlled so that an average cooling rate in passing through a temperature region of the melting point of the single crystal to 950° C. is in the range of 0.96° C./min or more, an average cooling rate in passing through a temperature region of 1150° C. to 1080° C. is in the range of 0.88° C./min or more, and an average cooling rate in passing through a temperature region of 1050° C. to 950° C. is in the range of 0.71° C./min or more.
    Type: Grant
    Filed: October 19, 2004
    Date of Patent: September 29, 2009
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Ryoji Hoshi, Susumu Sonokawa
  • Patent number: 7582160
    Abstract: In silicon single crystal growth by the Czochralski method using a quartz crucible, a silicon single crystals with a uniform distribution of oxygen concentration can be produced in high yield without being affected by changes of crystal diameter and initial amount of melt feedstock. The oxygen concentration is adjusted by estimating oxygen concentration during growth on the basis of a relationship among three parameters: crucible rotation rate (?), crucible temperature (T), and the ratio (?) of contact area of molten silicon with the inner wall of the crucible and with atmospheric gas, and by associating the temperature (T) with the ratio (?) by the function 1/?×Exp(?E/T) where E is the dissolution energy (E) of quartz into molten silicon to control at least one of the rotation rate (?) and temperature (T) to conform the estimated oxygen concentration to a target concentration.
    Type: Grant
    Filed: June 13, 2006
    Date of Patent: September 1, 2009
    Assignee: Siltronic AG
    Inventors: Yutaka Kishida, Seiki Takebayashi, Teruyuki Tamaki
  • Patent number: 7563319
    Abstract: An active layer side silicon wafer is heat-treated in an oxidizing atmosphere to thereby form a buried oxide film therein. The active layer side silicon wafer is then bonded to a supporting side wafer with said buried oxide film interposed therebetween thus to fabricate an SOI wafer. Said oxidizing heat treatment is carried out under a condition satisfying the following formula: [Oi]?2.123×1021exp(?1.035/k(T+273)), where, T is a temperature of the heat treatment, and [Oi] (atmos/cm3) is an interstitial oxygen concentration.
    Type: Grant
    Filed: December 19, 2003
    Date of Patent: July 21, 2009
    Assignee: Sumitomo Mitsubishi Silicon Corporation
    Inventors: Shigeru Umeno, Masataka Hourai, Masakazu Sano, Shinichiro Miki
  • Patent number: 7544246
    Abstract: In a process for manufacturing a LT substrate from a LT crystal, after growing the crystal, a LT substrate in ingot form is imbedded in carbon power, or is place in a carbon vessel, and heat treated is conducted at a maintained temperature of between 650° C. and 1650° C. for at least 4 hours, whereby in a lithium tantalate (LT) substrate, sparks are prevented from being generated by the charge up of an electric charge on the substrate surface, and thereby destruction of a comb pattern formed on the substrate surface and breaks or the like in the LT substrate are prevented.
    Type: Grant
    Filed: August 22, 2006
    Date of Patent: June 9, 2009
    Assignee: Sumitomo Metal Mining Co., Ltd.
    Inventors: Tomio Kajigaya, Takashi Kakuta
  • Patent number: 7544247
    Abstract: In a process for manufacturing a LT substrate from a LT crystal, after growing the crystal, a LT substrate in ingot form is imbedded in carbon power, or is place in a carbon vessel, and heat treated is conducted at a maintained temperature of between 650° C. and 1650° C. for at least 4 hours, whereby in a lithium tantalate (LT) substrate, sparks are prevented from being generated by the charge up of an electric charge on the substrate surface, and thereby destruction of a comb pattern formed on the substrate surface and breaks or the like in the LT substrate are prevented.
    Type: Grant
    Filed: May 9, 2007
    Date of Patent: June 9, 2009
    Assignee: Sumitomo Metal Mining Co., Ltd.
    Inventors: Tomio Kajigaya, Takashi Kakuta
  • Patent number: 7544248
    Abstract: In a process for manufacturing a LT substrate from a LT crystal, after growing the crystal, a LT substrate in ingot form is imbedded in carbon power, or is place in a carbon vessel, and heat treated is conducted at a maintained temperature of between 650° C. and 1650° C. for at least 4 hours, whereby in a lithium tantalate (LT) substrate, sparks are prevented from being generated by the charge up of an electric charge on the substrate surface, and thereby destruction of a comb pattern formed on the substrate surface and breaks or the like in the LT substrate are prevented.
    Type: Grant
    Filed: August 14, 2007
    Date of Patent: June 9, 2009
    Assignee: Sumitomo Metal Mining Co., Ltd.
    Inventors: Tomio Kajigaya, Takashi Kakuta
  • Patent number: 7537658
    Abstract: An oxide film 13 on the surface of the substrate 11 and an inner wall oxide film 112 in a COP 111 exposed to the surface of the substrate 11 are removed by cleaning the surface of the substrate 11 with a hydrofluoric acid solution. The substrate 11 is then cleaned with ozone water, thereby forming an oxide film 13 on the surface of the substrate 11. Thereafter the substrate 11 is subjected to a heat treatment for removing the oxide film 13 on the surface of the substrate 11. Consequently, the COP 111 on the surface of the substrate 11 is planarized to be eliminated from the substrate surface. Thereafter an epitaxial layer 12 is formed on the surface of the substrate 11.
    Type: Grant
    Filed: December 20, 2005
    Date of Patent: May 26, 2009
    Assignee: Sumco Techxiv Corporation
    Inventors: Yuichi Nasu, Kazuhiro Narahara
  • Patent number: 7473314
    Abstract: A silicon single crystal is grown using the Czochralski method. During the crystal growth, a thermal stress is applied to at least a portion of the silicon single crystal. A gaseous substance containing hydrogen atoms is used as an atmospheric gas for growing the crystal.
    Type: Grant
    Filed: March 28, 2006
    Date of Patent: January 6, 2009
    Assignee: Sumco Corporation
    Inventors: Shuichi Inami, Nobumitsu Takase, Yasuhiro Kogure, Ken Hamada, Tsuyoshi Nakamura
  • Patent number: 7470323
    Abstract: The Czochralski method is used for producing p?-doped and epitaxially coated semiconductor wafers from silicon, wherein a silicon single crystal is pulled, and during the pulling is doped with boron, hydrogen and nitrogen, and the single crystal thus obtained is processed to form p?-doped semiconductor wafers which are epitaxially coated.
    Type: Grant
    Filed: October 11, 2007
    Date of Patent: December 30, 2008
    Assignee: Siltronic AG
    Inventors: Wilfried von Ammon, Katsuhiko Nakai, Martin Weber, Herbert Schmidt, Atsushi Ikari
  • Publication number: 20080292523
    Abstract: A production method of a silicon single crystal wafer capable of effectively bringing out a gettering effect also in a thin film device is provided: wherein a thermal treatment with rapid heating up and down is performed for 10 seconds or shorter on a silicon single crystal wafer obtained by processing a single crystal grown by the Czochralski method and having an initial interstitial oxygen density is 1.4×1018 atoms/cc (ASTM F-121, 1979).
    Type: Application
    Filed: May 1, 2008
    Publication date: November 27, 2008
    Applicant: SUMCO Corporation
    Inventors: Toshiaki ONO, Takayuki KIHARA
  • Publication number: 20080286565
    Abstract: A method for manufacturing an epitaxial wafer includes: a step of pulling a single crystal from a boron-doped silicon melt in a chamber based on a Czochralski process; and a step of forming an epitaxial layer on a surface of a silicon wafer sliced from the single crystal. The single crystal is allowed to grow while passed through a temperature region of 800 to 600° C. in the chamber in 250 to 180 minutes during the pulling step. The grown single crystal has an oxygen concentration of 10×1017 to 12×1017 atoms/cm3 and a resistivity of 0.03 to 0.01 ?cm. The silicon wafer is subjected to pre-annealing prior to the step of forming the epitaxial layer on the surface of the silicon wafer, for 10 minutes to 4 hours at a predetermined temperature within a temperature region of 650 to 900° C. in an inert gas atmosphere. The method is to fabricate an epitaxial wafer that has a diameter of 300 mm or more, and that attains a high IG effect, and involves few epitaxial defects.
    Type: Application
    Filed: November 2, 2007
    Publication date: November 20, 2008
    Inventors: Yasuo Koike, Toshiaki Ono, Naoki Ikeda, Tomokazu Katano
  • Patent number: 7442253
    Abstract: The present invention is directed to a process for producing a silicon wafer which, during the heat treatment cycles of essentially any arbitrary electronic device manufacturing process, may form an ideal, non-uniform depth distribution of oxygen precipitates and may additionally contain an axially symmetric region which is substantially free of agglomerated intrinsic point defects. The process either comprises exposing the wafer's front and back surfaces to different atmospheres, or thermally annealing two wafers in a face-to-face arrangement.
    Type: Grant
    Filed: May 24, 2007
    Date of Patent: October 28, 2008
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Robert J. Falster, Joseph C. Holzer, Marco Cornara, Daniela Gambaro, Massimiliano Olmo, Steve A. Markgraf, Paolo Mutti, Seamus A. McQuaid, Bayard K. Johnson
  • Patent number: 7435294
    Abstract: A silicon single crystal is manufactured by growing said crystal composed of a defect-free area free from the Grown-in defects by the CZ process, adding a gas of a hydrogen atom-containing substance to an atmosphere gas within a growing apparatus, and doping nitrogen and/or carbon in the crystal. Therefore, a wafer the whole surface of which is composed of the defect-free area free from the Grown-in defects and which can sufficiently and uniformly form BMD can be easily sliced. Such a wafer can be extensively used, since it can significantly reduce generation of characteristic defectives of integrated circuits to be formed thereon and contribute for improving the production yield as a substrate responding to the demand for further miniaturization and higher density of the circuits.
    Type: Grant
    Filed: March 31, 2006
    Date of Patent: October 14, 2008
    Assignee: Sumco Corporation
    Inventors: Toshiaki Ono, Wataru Sugimura, Masataka Hourai
  • Patent number: 7431765
    Abstract: A process for producing a single crystal silicon wafer comprising a front surface, a back surface, a lateral surface joining the front and back surfaces, a central axis perpendicular to the front and back surfaces, and a segment which is axially symmetric about the central axis extending substantially from the front surface to the back surface in which crystal lattice vacancies are the predominant intrinsic point defect, the segment having a radial width of at least about 25% of the radius and containing agglomerated vacancy defects and a residual concentration of crystal lattice vacancies wherein (i) the agglomerated vacancy defects have a radius of less than about 70 nm and (ii) the residual concentration of crystal lattice vacancy intrinsic point defects is less than the threshold concentration at which uncontrolled oxygen precipitation occurs upon subjecting the wafer to an oxygen precipitation heat treatment.
    Type: Grant
    Filed: March 24, 2005
    Date of Patent: October 7, 2008
    Assignee: MEMC Electronic Materials, Inc.
    Inventors: Robert J. Falster, Vladimir V. Voronkov, Paolo Mutti, Francesco Bonoli
  • Patent number: 7431764
    Abstract: The axial temperature gradient G at the vicinity of the solid-liquid interface 24 in an ingot is calculated in consideration of the heating value of a heater 18, the dimensions and physical property values of furnace inside components and the convection of the melt 12 before pulling up the single crystal ingot 15 by a puller 10 by use of a numerical simulation of synthetic heater transfers and a numerical simulation of melt convection. Then, the pulling velocity V of the single crystal ingot is determined from an value experienced of the ratio C=V/G of the pulling velocity V and the axial temperature gradient G of the single crystal ingot at which the single crystal ingot becomes defect-free, obtained when the single crystal ingot was pulled up by a same type puller as the puller in the past, and the axial temperature gradient G calculated by use of the simulations.
    Type: Grant
    Filed: February 17, 2006
    Date of Patent: October 7, 2008
    Assignee: Sumco Corporation
    Inventors: Senlin Fu, Naoki Ono
  • Publication number: 20080236476
    Abstract: A silicon single crystal wafer for a particle monitor is presented, which wafer has an extremely small amount in the surface density of light point defects and is capable of still maintaining a small surface density even after repeating the SC-1. The wafer is prepared by slicing a silicon single crystal ingot including an area in which crystal originated particles are generated, and the surface density of particles having a size of not less than 0.12 mum is not more than 15 counts/cm2 after repeating the SC-1. More preferably, a silicon single crystal wafer having a nitrogen concentration of 1×1013 1×1015 atoms/cm3 provides a surface density of not more than 1 counts/cm2 for the particles having a diameter of not less than 0.12 mum even after repeating the SC-1. Hence, a high quality wafer optimally used for a particle monitor can be obtained and a very small number of defects in the wafer make it possible to produce devices.
    Type: Application
    Filed: May 23, 2008
    Publication date: October 2, 2008
    Inventors: Hiroki Murakami, Masahiko Okui, Hiroshi Asano
  • 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: 7384477
    Abstract: The present invention is a method for producing a single crystal with pulling the single crystal from a raw material melt in a chamber by CZ method, wherein when growing the single crystal, where a pulling rate is defined as V and a temperature gradient of the crystal is defined as G during growing the single crystal, the temperature gradient G of the crystal is controlled by changing at least two or more of pulling conditions. Thereby, there is provided a method for producing a single crystal in which when the single crystal is grown by CZ method, V/G can be controlled without lowering a pulling rate V, and thus the single crystal including a desired defect region can be produced effectively for a short time.
    Type: Grant
    Filed: May 28, 2004
    Date of Patent: June 10, 2008
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Masahiro Sakurada, Makoto Iida, Nobuaki Mitamura, Atsushi Ozaki
  • 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