With Liquid Flow Control Or Manipulation During Growth (e.g., Mixing, Replenishing, Magnetic Levitation, Stabilization, Convection Control, Baffle) Patents (Class 117/30)
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Patent number: 6569236Abstract: A device for producing single-crystal ingot, provided with coolers (19) using a piping system through which cooling water failure caused by water leakage and at the same time to find out conditions for maximizing a production efficiency, the coolers (19) are disposed at portions of the inner sides of thermal shielding elements (18) and the lower ends (19a) of cooling pipes are so set as to be positioned up to 150 mm high from the surface (12a) of molten silicon liquid.Type: GrantFiled: September 27, 2001Date of Patent: May 27, 2003Assignee: Komatsu Denshi Kinzoku Kabushiki KaishaInventors: Shigeo Morimoto, Hiroshi Monden, Daisuke Ebi, Toshirou Kotooka
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Patent number: 6565822Abstract: An epitaxial silicon wafer, which has no projections having a size of 100 nm or more and a height of 5 nm or more on an epitaxial layer, and a method for producing an epitaxial silicon wafer, wherein a single crystal ingot containing no I-region is grown when a silicon single crystal is grown by the CZ method, and an epitaxial layer is deposited on a silicon wafer sliced from the single crystal ingot and containing no I-region for the entire surface. An epitaxial wafer of high quality with no projection-like surface distortion observed as particles on an epi-layer surface is provided by forming a wafer having no I-region for the entire surface from a single crystal and depositing an epitaxial layer thereon, and a single crystal having no I-region for entire plane is produced with good yield and high productivity, thereby improving productivity of epi-wafers and realizing cost reduction.Type: GrantFiled: September 21, 2000Date of Patent: May 20, 2003Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Ryoji Hoshi, Susumu Sonokawa, Masahiro Sakurada, Tomohiko Ohta, Izumi Fusegawa
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Patent number: 6565652Abstract: An improved method of obtaining a wafer exhibiting high resistivity while preventing the reduction of resistivity due to the generation of oxygen donors provided by: a) using the CZ method to grow a silicon single crystal ingot in the presence of a magnetic field, such crystal having a resistivity of 100 &OHgr;·cm or more and an initial interstitial oxygen concentration of 5 to 10 ppma and b) processing the ingot into a wafer.Type: GrantFiled: December 6, 2001Date of Patent: May 20, 2003Assignee: SEH America, Inc.Inventors: Oleg V. Kononchuk, Sergei V. Koveshnikov, Zbigniew J. Radzimski, Neil A. Weaver
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Publication number: 20030079674Abstract: A semiconductor substrate after heat-treatment in a non-oxidising atmosphere has the characteristics that the depth of the denuded zone may be greater than 12 &mgr;m or the defect-free depth of the void type defect is greater than 12 &mgr;m and the substrate has a locally densified portion produced by nitrogen segregation and exhibiting a signal strength two or more times the average signal strength at the depth of 12 &mgr;m or more below the surface thereof when measuring the concentration of nitrogen by using secondary ion mass-spectroscopy, and the density of the crystal defect of oxygen precipitates is 5×108/cm3 or more, and the said substrate is produced by heat-treating for at least one hour at the temperature of 1200° C. or more in a non-oxidising atmosphere.Type: ApplicationFiled: August 7, 2002Publication date: May 1, 2003Applicant: Wacker Siltronic Gesellschaft Fur Halbleitermaterialien AGInventors: Akiyoshi Tachikawa, Kazunori Ishisaka, Atsushi Ikari
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Publication number: 20030056715Abstract: A silicon semiconductor substrate has a structure possessing oxygen precipitate defects fated to form gettering sites in a high density directly below the defect-free region of void type crystals. The silicon semiconductor substrate is formed by heat-treating a silicon semiconductor substrate derived from a silicon single crystal grown by the Czochralski method or the magnetic field-applied Czochralski method and characterized by satisfying the relational expression (Oi DZ)−(COP DZ)≦10 &mgr;m wherein Oi DZ denotes a defect-free zone of oxygen precipitate crystal defects and COP DZ denotes a region devoid of a void type defect measuring not less than 0.11 &mgr;m in size, and having not less than 5×108 oxygen precipitate crystal defects per cm3.Type: ApplicationFiled: September 6, 2002Publication date: March 27, 2003Applicant: Wacker Siltronic Gesellschaft Fur Halbleitermaterialien AGInventors: Akiyoshi Tachikawa, Atsushi Ikari
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Publication number: 20030041797Abstract: A feed rod for growing a magnetic single crystal having a composition represented by the formula (Y3-aAa)(Fe5-b-cBb)O12-&agr;, wherein A is at least one element selected from the lanthanoide series, B is at least one element selected from the group consisting of Ga, Al, In, and Sc, c is a value for decreasing the Fe content from the stoichiometric amount, &agr; is a value for decreasing the oxygen content to satisfy the chemically neutral condition, and the relationships 0≦a≧0.5; 0≦b≧1.0; 0<c≧0.15 and 0<&agr; are satisfied.Type: ApplicationFiled: August 15, 2002Publication date: March 6, 2003Inventor: Mikio Geho
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Patent number: 6527852Abstract: A semiconductor crystal growing apparatus includes a device for applying a magnetic field to inside a semiconductor melt and a device for passing a current through the semiconductor melt. An electrode for applying the current to the inside of the semiconductor melt extends through a tube surrounding the electrode.Type: GrantFiled: April 18, 2001Date of Patent: March 4, 2003Assignee: NEC CorporationInventors: Masahito Watanabe, Minoru Eguchi
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Patent number: 6497761Abstract: An apparatus for growing a single crystal of semiconductor is provided, which makes it possible to grow a heavy single crystal of semiconductor of 100 kg or greater in weight even if a growing single crystal contains a neck. In the apparatus, the first and second electrodes are provided such that the first ends of the first and second electrodes are electrically connected to the power supply and the second ends of the first and second electrodes are contacted with the melt in the crucible. During the growth process, a specific voltage is applied across the first ends of the first and second electrodes, thereby forming the electrical current path interconnecting the second ends of the first and second electrodes in the melt. The magnetic field is generated with the magnetic field generator to intersect with the electrical current path in the melt. No electric current flows through the growing single crystal from the melt.Type: GrantFiled: March 6, 2001Date of Patent: December 24, 2002Assignee: NEC CorporationInventors: Masahito Watanabe, Minoru Eguchi
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Publication number: 20020157600Abstract: In a method manufacturing a silicon single crystal 8 according to an MCZ method, a flow rate of an inert gas flowing in a growth furnace 1 during growth of the silicon single crystal 8 and/or a pressure in the growth furnace 1 is altered according to a pulling amount of the silicon single crystal 8 to adjust an interstitial oxygen concentration therein. By altering a flow rate of an inert gas flowing in the growth furnace or a pressure therein, an amount of oxygen evaporating as an oxide from a surface of a silicon melt 10 in the vicinity of a crystal growth interface can be easily adjusted, and thereby, an oxygen amount included in the silicon melt 10 can be controlled with ease.Type: ApplicationFiled: October 24, 2001Publication date: October 31, 2002Inventors: Izumi Fusegawa, Ryoji Hoshi, Kouichi Inokoshi, Tomohiko Ohta
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Patent number: 6458202Abstract: A Czochralski method of producing a single crystal silicon ingot having a uniform thermal history. In the process, the power supplied to the side heater is maintained substantially constant throughout the growth of the main body and end-cone of the ingot, while power supplied to a bottom heater is gradually increased during the growth of the second half of the main body and the end-cone. The present process enables an ingot to be obtained which yields wafers having fewer light point defects in excess of about 0.2 microns, while having improved gate oxide integrity.Type: GrantFiled: June 19, 2000Date of Patent: October 1, 2002Assignee: MEMC Electronic Materials, Inc.Inventors: Makoto Kojima, Yasuhiro Ishii
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Patent number: 6458204Abstract: A method of producing high-quality and large-diameter single crystals by the Czochralski method is disclosed which can provide wafers with a minimized number of such grown-in defects as dislocation clusters and laser scattering tomography defects. Specifically, it is a method of producing silicon single crystals which comprises carrying out the crystal pulling while maintaining the solid-melt interface during pulling in the shape of an upward convex with the central portion of the interface being higher by at least 5 mm than the peripheral region thereof and while applying a magnetic field, and optionally in addition to the above, while maintaining the temperature gradient in the direction of axis of pulling in the peripheral region at a level lower than that in the central portion in the range of from the melting point to 1,200° C.Type: GrantFiled: November 22, 2000Date of Patent: October 1, 2002Assignee: Sumitomo Metal Industries, Ltd.Inventors: Masahiko Okui, Hiroki Murakami, Kazuyuki Egashira, Makoto Ito, Hiroshi Hayakawa, Kelly Garret, Yoshinori Shirakawa
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Patent number: 6423285Abstract: In a method for producing a silicon single crystal by growing a single crystal ingot while a magnetic field perpendicular to a crystal growth axis is applied to a silicon melt contained in a quartz crucible during pulling of the single crystal from the melt contained in the quartz crucible, the crystal growth is performed so that one of a low temperature region and a high temperature region generated at a surface of the silicon melt contained in the crucible should always cover a solid-liquid interface of the crystal growth, or a ratio of vertical magnetic field component to horizontal magnetic field component for magnetic field strength at the crystal center of the surface of the silicon melt contained in the quartz crucible is controlled to be 0.3 or more and 0.5 or less.Type: GrantFiled: November 7, 2000Date of Patent: July 23, 2002Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Kirio Itoi, Eiichi Iino, Tohru Ishizuka, Tomohiko Ohta, Izumi Fusegawa
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Patent number: 6350312Abstract: A process for preparing strontium doped molten silicon for use in a single silicon crystal growing process is disclosed. Polysilicon is doped strontium and melted in a silica crucible. During melting and throughout the crystal growing process the strontium acts as a devitrification promoter and creates a layer of devitrified silica on the inside crucible surface in contact with the melt resulting in a lower level of contaminants in the melt and grown crystal.Type: GrantFiled: March 8, 2000Date of Patent: February 26, 2002Assignee: MEMC Electronic Materials, Inc.Inventors: Richard Joseph Phillips, Steven Jack Keltner, John Davis Holder
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Publication number: 20020020340Abstract: A method of manufacturing a damage-resistant silicon wafer is provided. The method comprises adding polycrystalline silicon to a crucible, adding a nitrogen-containing dopant to the crucible, heating the polycrystalline silicon to form a melt of nitrogen-doped silicon, pulling a nitrogen-doped silicon crystal from the melt using a seed crystal according to the Czochralski technique, forming a silicon wafer from the silicon crystal, the silicon wafer having an edge, and rounding the edge of the silicon wafer. The method may optionally include applying an electrical potential across the crucible while pulling the nitrogen-doped silicon crystal from the melt.Type: ApplicationFiled: January 11, 2001Publication date: February 21, 2002Applicant: SEH America, Inc.Inventors: Gerald R. Dietze, Sean G. Hanna, Zbigniew J. Radzimski
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Publication number: 20010017100Abstract: A process for dendritic web growth is described. The process includes providing a melt, growing a dendritic web crystal from the melt, replenishing the melt during the step of growing the dendritic web crystal, and applying a magnetic field to the melt during the step of growing the dendritic web crystal.Type: ApplicationFiled: February 22, 2001Publication date: August 30, 2001Inventors: Daniel L. Meier, Gregory T. Neugebauer, Edward V. Macuga, Robert P. Stoehr, Philip J. Simpson, Jalal Salami
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Patent number: 6267816Abstract: This is a method for growing by pulling single crystals 6 using CZ process from material melt 5 to which cusp magnetic field is applied. Inside diameter U of the crucible 3 that contains the material melt 5 is (Y+140 mm) or larger and less than 3Y, where Y stands for outside diameter of the single crystal 6. When cusp magnetic field is applied, high pulling yield is maintained even if the inside diameter U of the crucible is small. Oxygen yield and dislocation free yield are improved by reducing inside diameter U of the crucible. As a result, the yield of manufacturing single crystals 6 is improved.Type: GrantFiled: March 23, 1999Date of Patent: July 31, 2001Assignee: Sumitomo Sitix CorporationInventor: Teruo Izumi
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Patent number: 6261364Abstract: A system for growing high-quality, low-carbon-concentration single crystals which have an excellent gas-flow guiding function near the melt, containing 1) an inverted conical, flow-guide cover placed above and coaxially with a double-walled crucible, with its lower end located immediately above the surface of the melt and in the space between the outer surface of the single crystal to be grown and the inner surface of the sidewall of the inner crucible; 2) a short passage comprising a hole passing through the sidewall of the inner crucible at a position higher than the level of the melt; and 3) a flow guide cylinder placed above and coaxially with the double-walled crucible, with its lower end located immediately above the surface of the melt and in the space between the outer surface of the sidewall of the inner crucible and the inner surface of the sidewall of the outer crucible, all arranged in a furnace.Type: GrantFiled: September 1, 1998Date of Patent: July 17, 2001Assignees: Mitsubishi Materials Corporation, Mitsubishi Materials Silicon CorporationInventors: Yoshiaki Arai, Keisei Abe, Norihisa Machida
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Patent number: 6261361Abstract: There is disclosed a method for producing a silicon single crystal wafer wherein a silicon single crystal is grown in accordance with the CZ method with doping nitrogen in an N-region in a defect distribution chart which shows a defect distribution in which the horizontal axis represents a radial distance D (mm) from the center of the crystal and the vertical axis represent a value of F/G (mm2/° C.·min), where F is a pulling rate (mm/min) of the single crystal, and G is an average intra-crystal temperature gradient(° C./mm) along the pulling direction within a temperature range of the melting point of silicon to 1400° C. There can be provided a method of producing a silicon single crystal wafer consisting of N-region where neither V-rich region nor I-rich region is present in the entire surface of the crystal by CZ method, under the condition that can be controlled easily in a wide range, in high yield, and in high productivity.Type: GrantFiled: May 19, 2000Date of Patent: July 17, 2001Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Makoto Iida, Masaro Tamatsuka, Masanori Kimura, Shozo Muraoka
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Patent number: 6258163Abstract: A method for producing a high-quality silicon single crystal in which oxygen distribution, with respect to the growth and radial directions, is made uniform. The invention provides a magnetic Czochralski method involving pulling a single crystal while a cusp magnetic field is applied, the intensity of the cusp magnetic field and a mid-field position existing between upper and lower coils being held constant during pulling of a main body of the single crystal, having a diameter corresponding to that of a wafer product; said mid-field position being set at a specific range defined in terms of the surface level of a melt. Preferably, the cusp magnetic field held constant during a pulling step has an intensity of 300 G to 600 G; the mid-field position is set at −40 mm to −100 mm from the surface level of a melt; and the mid-field position is set at −7% to −18% from the surface level of the melt as normalized with respect to the inner diameter of a crucible.Type: GrantFiled: September 8, 1999Date of Patent: July 10, 2001Assignee: Sumitomo Metal Industries, Ltd.Inventor: Shunji Kuragaki
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Patent number: 6200384Abstract: In the growth of a large silicon single crystal weighing not less than 100 kg by the Czokralski method resorting to application of a magnetic field, a crucible, not less than 0.7 m in inside diameter is used, and a cusped magnetic field which manifests a maximum intensity of not more than 1000 gausses on the inner wall of the crucible is applied.Type: GrantFiled: July 27, 1999Date of Patent: March 13, 2001Assignee: Nippon Steel CorporationInventors: Yutaka Kishida, Wataru Ohashi, Teruyuki Tamaki, Seiki Takebayashi
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Patent number: 6190452Abstract: There is disclosed a method for producing a silicon single crystal in accordance with the Czochralski method wherein a crystal is pulled with controlling a temperature in a furnace so that &Dgr;G may be 0 or a negative value, where &Dgr;G is a difference between the temperature gradient Gc (° C./mm) at the center of a crystal and the temperature gradient Ge (° C./mm) at the circumferential portion of the crystal, namely &Dgr;G=(Ge−Gc), wherein G is a temperature gradient in the vicinity of a solid-liquid interface of a crystal from the melting point of silicon to 1400° C.Type: GrantFiled: June 8, 1999Date of Patent: February 20, 2001Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Masahiro Sakurada, Hideki Yamanaka, Tomohiko Ohta
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Patent number: 6179911Abstract: This invention provides a method and a apparatus capable of manufacturing single crystals with an oxygen density of less than 12×1017 atoms/cm3 or less than 10×1017 atoms/cm3, and wherein the oxygen density of the single crystal produced is uniformly distributed along its longitudinal axis. The electrical power inputted into the main heater 6 surrounding the quartz crucible 4 and the top heater 9 shaped like a reverse frustrated cone and disposed above the quartz crucible 4, is controlled to keep the temperature of the melt 5 in a preset range during the process of pulling up the single crystal silicon 10. When combining the main heater 6 and the top heater 9, the heat emitted from the main heater 6 can be kept small, and the heat load on the quartz crucible 4 and the amount of oxygen released from the quartz crucible 4 and dissloved into melt 5 can be reduced.Type: GrantFiled: October 25, 1999Date of Patent: January 30, 2001Assignee: Kamatsu Electronic Metals Co., Ltd.Inventors: Junsuke Tomioka, Hiroshi Inagaki, Fumitaka Ishikawa
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Patent number: 6159438Abstract: In method for manufacturing a silicon single crystal in accordance with a Czochralski method, during the growth of the silicon single crystal, pulling is performed such that a solid-liquid interface in the crystal, excluding a peripheral 5 mm-width portion, exists within a range of an average vertical position of the solid-liquid interface.+-. 5 mm. There is also disclosed a method for manufacturing a silicon single crystal in accordance with the Czochralski method, wherein during the growth of a silicon single crystal, a furnace temperature is controlled such that a temperature gradient difference .DELTA.G (=Ge-Gc) is not greater than 5.degree. C./cm, where Ge is a temperature gradient (.degree. C./cm) at a peripheral portion of the crystal, and Gc is a temperature gradient (.degree. C./cm) at a central portion of the crystal, both in an in-crystal descending temperature zone between 1420.degree. C. and 1350.degree. C. or between a melting point of silicon and 1400.degree. C.Type: GrantFiled: July 22, 1999Date of Patent: December 12, 2000Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Makoto Iida, Eiichi Iino, Masanori Kimura, Shozo Muraoka, Hideki Yamanaka
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Patent number: 6156119Abstract: In a method for producing a silicon single crystal of high quality, the silicon single crystal is grown based on a magnetic field applied Czochralski method. The single crystal is grown at a high growth rate satisfying the equation Vave.gtoreq.120/r, where Vave denotes an average crystal growth rate, and r denotes a radius of the single crystal, and a rotation number R of the single crystal in growing satisfies the equation R.ltoreq.1250/r. Oxygen concentration in-plane distribution is 10% or less, and a deformation ratio of a constant diameter portion in the silicon single crystal in a direction perpendicular to a crystal growth axis direction is 5% or less. The silicon single crystal has a high uniformity of oxygen concentration in-plane distribution without deformation of crystal, even if the crystal is grown at a growth rate exceeding the upper limits found in conventional techniques.Type: GrantFiled: March 17, 1999Date of Patent: December 5, 2000Assignee: Shin-etsu Handotai Co., Ltd.Inventors: Ryoji Hoshi, Kouichi Inokoshi, Tomohiko Ohta
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Patent number: 6117230Abstract: A process for producing a silicon single crystal by the Czochralski method, utilizes a heater which is intended for heating a silicon-filled crucible and is arranged below the crucible. The process has energy delivered to the melt at least some of the time inductively using a coiled heater arranged under the crucible. The heater is in the form of a wound coil.Type: GrantFiled: November 25, 1997Date of Patent: September 12, 2000Assignee: Wacker Siltronic Gesellschaft fur Halbleitermaterialien AGInventors: Wilfried Von Ammon, Erich Tomzig, Paul Fuchs, Yuri Gelfgat
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Patent number: 6117231Abstract: A silicon wafer sliced from a silicon single crystal having a low oxygen concentration is used as an epitaxial substrate to provide semiconductor silicon single crystal wafers exhibiting good electrical characteristics at a low cost. A semiconductor silicon single crystal having a resistivity in a range of 0.005 to 0.02 .OMEGA..multidot.cm and an oxygen concentration of 12.times.10.sup.17 atoms/cm.sup.3 (ASTM'79) or less is manufactured by a Czochralski (CZ) method. The resulting silicon single crystal is shaped into a silicon single crystal substrate on which a silicon single crystal is epitaxially grown.Type: GrantFiled: April 13, 1999Date of Patent: September 12, 2000Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Izumi Fusegawa, Toshirou Hayashi, Ryoji Hoshi, Tomohiko Ohta
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Patent number: 6113688Abstract: A method of growing a single crystal, comprises pulling a single crystal from molten material in a crucible by the Czochralski method; simultaneously applying an axially symmetric, radial cusp magnetic field to the molten material; and simultaneously heating the crucible from both the bottom and the sides; where a ratio of the heating from the bottom of the crucible, q, to the total heating of the crucible, Q, is q/Q, and during the pulling the ratio q/Q changes. The concentration of oxygen in the pulling direction of the crystal may be accurately controlled, and is uniform.Type: GrantFiled: October 1, 1998Date of Patent: September 5, 2000Assignee: Sumitomo Metal Industries, Ltd.Inventors: Souroku Kawanishi, Makoto Itou
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Patent number: 6110272Abstract: A method of loading a crucible, comprises loading at least one polycrystalline silicon rod into the crucible. Lump and/or granular polycrystalline silicon may also be loaded into the crucible. Especially when loaded into the crucible in a close-packed pyramidal configuration, a high loading density is achieved.Type: GrantFiled: September 29, 1998Date of Patent: August 29, 2000Assignee: Sumitomo Sitix CorporationInventors: Katsunori Aikawa, Kuniharu Inoue
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Patent number: 6086671Abstract: A method for melting a silicon starting material can suppress silica (SiO2) from melting out from a quartz crucible wherein the silicon starting material is melted and can provide a high-quality silicon single crystal in a high yield. The growth method comprises melting the silicon starting material charged in the crucible while applying thereto a static magnetic field, contacting a seed crystal to a surface of the silicon melt, and pulling the seed crystal upwardly to solidify the contacted melt. The silicon starting material charged in the crucible, which is under melting, is applied with a static magnetic field such as a Cusp magnetic field, a horizontal magnetic field and/or a vertical magnetic field. The application can control heat convection occurring in the crucible during the course of the melting of the starting material, thereby obtaining a silicon single crystal having a reduced number of dislocation defects.Type: GrantFiled: September 1, 1998Date of Patent: July 11, 2000Assignee: Sumitomo Sitix CorporationInventors: Souroku Kawanishi, Youichi Yamamoto
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Patent number: 6080238Abstract: After whole raw material filled in a crucible is melted by plural heaters provided around the crucible, outputs of the heaters are lowered so that molten liquid is maintained at a predetermined temperature. A seed crystal is brought into contact with a surface of the molten liquid, and while a height of the surface of the molten liquid is being maintained in a heating region of a topmost heater, a pulling shaft is pulled up at a predetermined speed so that a single crystal is grown in a lower position of the seed crystal. At this time, in order that the pulled single crystal has required oxygen concentration during the pulling of the single crystal, a ratio of the output of the topmost heater to the outputs of all the heaters is set to a value calculated by R.sub.PW .gtoreq.0.88R.sub.T (R.sub.PW : output ratio of the topmost heater) based on the ratio R.sub.T of the height of the topmost heater to the height of the crucible.Type: GrantFiled: August 31, 1998Date of Patent: June 27, 2000Assignee: Sumitomo Sitix CorporationInventor: Makoto Ito
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Patent number: 6080237Abstract: This invention is directed to a method for the production of a dislocation-free silicon single crystal by the Czochralski method. This method attains growth of the main body part of the dislocation-free silicon single crystal by immersing a seed crystal in a melt of silicon and then pulling the seed crystal without recourse to the necking. The seed crystal thus used is a dislocation-free silicon single crystal. The horizontal maximum length of the part of the seed crystal being immersed in the melt at the time of completing the immersion of the seed crystal in the melt is not less than 5 mm. The immersing rate of the seed crystal in the melt is not more than 2.8 mm/min and the part of the seed crystal to be immersed in the melt is a crystal as grown.Type: GrantFiled: June 8, 1998Date of Patent: June 27, 2000Assignees: Nippon Steel Corporation, NSC Electron CorporationInventors: Toshio Iwasaki, Shin-ichi Fujimoto, Hiroshi Isomura, Takayoshi Ishida, Michiharu Tamura, Atsushi Ikari
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Patent number: 6077346Abstract: In the growth of a semiconductor single crystal according to the Czochralski method, a magnetic field is generated in a semiconductor melt and a current is supplied in the semiconductor melt in a direction perpendicular to the magnetic field. This makes it possible to cause the semiconductor melt to rotate spontaneously without rotating the crucible, thereby to grow a single crystal of semiconductor without striation even when growing a single crystal of semiconductor having a large diameter. Also it is made possible to exactly control the rotation rate of the semiconductor melt by changing the intensity of the magnetic field and the magnitude of the current independently. Further, the distribution of the rotation rates in the semiconductor melt can also be varied by changing the position of electrodes or electrode protecting tubes for immersing in the semiconductor melt.Type: GrantFiled: December 11, 1998Date of Patent: June 20, 2000Assignee: NEC CorporationInventors: Masahito Watanabe, Minoru Eguchi
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Patent number: 6019837Abstract: A temperature sensor 42 is provided in a furnace 11, measuring temperature above a molten liquid 24 put in a crucible 12 to check proceedings of evaporation of oxygen vaporized from a free surface 44 of the molten liquid 24. From the data, and considering the relation with the oxygen dissolved into the crucible 12, the oxygen concentration in the molten liquid 24 can be found and the amount of oxygen taken into a single silicon crystal 40 pulled up from the molten liquid 24 can be figured out.Type: GrantFiled: November 25, 1997Date of Patent: February 1, 2000Assignees: Komatsu Electronic Metals Co., Ltd., Mitsubishi Materials Silicon Corporation, Kagaku Gijutsu Sinkou Jigyo Dan, Toshiba Ceramics Co., Ltd.Inventors: Susumu Maeda, Keisei Abe, Kazutaka Terashima, Hideo Nakanishi
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Patent number: 6019838Abstract: A crystal growing apparatus is able to provide dopant to a melt in the apparatus. A hopper is carrying dopant is integrated into a pull shaft of the apparatus so that dopant can be added to the melt without providing additional orifices in the apparatus or by opening the interior of the apparatus to the atmosphere.Type: GrantFiled: January 5, 1998Date of Patent: February 1, 2000Assignee: MEMC Electronic Materials, Inc.Inventor: Marcello Canella
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Patent number: 5997641Abstract: The hold member has a small-diameter portion and a large-diameter portion. An inner cylinder and an outer cylinder are disposed around the hold member in a concentric manner. The upper end of the hold member is affixed to a wire and suspended therefrom. A clearance is formed between the small-diameter portion and the inner cylinder. Clearances are created between the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder.Type: GrantFiled: December 8, 1997Date of Patent: December 7, 1999Assignee: Komatsu Electronic Metals Co., Ltd.Inventors: Mitsunori Kawabata, Yoshinobu Hiraishi, Mitsuo Usukubo, Ayumi Suda
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Patent number: 5976245Abstract: A Czochralski crystal growing system includes components for adding dopants to semiconductor materials and for growing single crystals. The components comprise a portion formed of a material that is chemically compatible with the semiconductor material. The portion includes a cavity sized to contain a desired amount of dopant. The cavity protects the dopant from exposure to contaminants, gas flows and heat in crystal growing furnaces. The portion is dipped into a melt to release the dopant. The portion can be a seed crystal which can further be used to grow a single crystal from the melt after doping. The components can include separate first and second portions formed of materials that are chemically compatible with the melt so that the portions can be placed into the melt. At least one of the first and second portions can contain a dopant. The second portion can be a seed crystal for growing a single crystal.Type: GrantFiled: June 12, 1998Date of Patent: November 2, 1999Assignee: SEH America, Inc.Inventor: Richard M. Aydelott
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Patent number: 5976246Abstract: A MCZ method in which the single crystal is pulled while being rotated under the conditions where the crystal growth rate V.sub.1 (mm/min) and the crystal circumference velocity V.sub.2 (mm/min) satisfy the following relationships:0.4.ltoreq.V.sub.10.628.times.10.sup.4 .ltoreq.V.sub.2 .ltoreq.1.0.times.10.sup.4andV.sub.2 .ltoreq.-3.72.times.10.sup.4 V.sub.1 +4.35.times.10.sup.4It is possible to manufacture a silicon single crystal with a large diameter with the MCZ method without causing distortion.Type: GrantFiled: November 19, 1997Date of Patent: November 2, 1999Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Eiichi Iino, Masanori Kimura, Shozo Muraoka
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Patent number: 5968263Abstract: An open loop control method for use with an apparatus for growing a silicon single crystal having a zero dislocation state and an improved diameter and growth rate uniformity in accordance with the Czochralski process. According to the invention, a heat and mass transfer model based on the silicon charged to a crucible is determined as a function of one or more reference parameters. The reference parameter values are determined from the growth of a reference silicon single crystal. A power profile is then determined as a function of the heat and mass transfer model for a given pull rate profile and model diameter profile. The power profile generated is representative of the power supplied to a heater for providing an amount of thermal energy to the crucible for substantially maintaining a thermal equilibrium at the interface between the melt and the crystal.Type: GrantFiled: April 1, 1998Date of Patent: October 19, 1999Assignee: MEMC Electronic Materials, Inc.Inventors: Sunil Grover, Steven L. Kimbel
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Patent number: 5968266Abstract: An apparatus for manufacturing a single crystal of silicon includes a crucible, a heater, electrodes, and a magnet. In addition to a plurality of heat generating portions and two main electrode portions, the heater has two or more auxiliary electrode portions. Two or more heater support members having an insulating property are further provided so as to support the heater through the auxiliary electrode portions. The number of heat generating portions which may be present between a heater support member and an electrode and between heater support members if adjacent to each other is equal to or less than 4. Each generating portion of the heater has a thickness of 25 mm or more. This structure makes it possible to produce a single crystal of silicon without causing breakage of a heater, even if a large electric current flows through the heater, even if a magnetic field of a high intensity is applied to a silicon melt in the crucible, and even if the heater has a large diameter.Type: GrantFiled: March 20, 1997Date of Patent: October 19, 1999Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Eiichi Iino, Masanori Kimura, Shozo Muraoka
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Patent number: 5968264Abstract: In method for manufacturing a silicon single crystal in accordance with a Czochralski method, during the growth of the silicon single crystal, pulling is performed such that a solid-liquid interface in the crystal, excluding a peripheral 5 mm-width portion, exists within a range of an average vertical position of the solid-liquid interface .+-.5 mm. There is also disclosed a method for manufacturing a silicon single crystal in accordance with the Czochralski method, wherein during the growth of a silicon single crystal, a furnace temperature is controlled such that a temperature gradient difference .DELTA.G (=Ge-Gc) is not greater than 5.degree. C./cm, where Ge is a temperature gradient (.degree.C./cm) at a peripheral portion of the crystal, and Gc is a temperature gradient (.degree.C./cm) at a central portion of the crystal, both in an in-crystal descending temperature zone between 1420.degree. C. and 1350.degree. C. or between a melting point of silicon and 1400.degree. C.Type: GrantFiled: July 2, 1998Date of Patent: October 19, 1999Assignee: Shin-etsu Handotai Co., Ltd.Inventors: Makoto Iida, Eiichi Iino, Masanori Kimura, Shozo Muraoka, Hideki Yamanaka
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Patent number: 5942032Abstract: A heat shield assembly is used in a Czochralski crystal puller for selectively shielding a monocrystalline ingot of semiconductor material to control the type and number density of agglomerated defects in the crystal structure of the ingot. The heat shield assembly has an upper heat shield connected to a lower heat shield. The upper and lower heat shields are connected to each other and slidingly connected to an intermediate heat shield. The lower heat shield is able to telescope up into the intermediate heat shield to minimize the profile of the heat shield assembly located within a crystal growth chamber of the crystal puller. However when needed to control formation of the monocrystalline ingot, the lower heat shield may be extended from the intermediate heat shield and project downwardly into the crystal puller crucible in close proximity to an upper surface of molten semiconductor source material in the crucible. A method employing the heat shield assembly is also disclosed.Type: GrantFiled: August 1, 1997Date of Patent: August 24, 1999Assignee: MEMC Electronic Materials, Inc.Inventors: Kyong-Min Kim, William L. Luter, Lee W. Ferry, Robert J. Braun, Srdjan Ilic, Mauro Dioda, Paolo Tosi, Marco Gobbo, Umberto Martini
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Patent number: 5938841Abstract: A novel device for producing a single crystal by the CZ or MCZ method is provided, which comprising a crucible for containing silicon melt therein, a wire reel and a wire for pulling a single crystal, a motor and a rotation shaft for rotating the crucible, a speed change device being inserted between the motor and the rotation shaft, and, if necessary, a magnetic field generator, by which the magnetic field is applied to the melt. According to the device for producing a single crystal, the rotation accuracy of a crucible can be improved, so that the concentrations of impurities in the pulled single crystal can be highly precisely controlled.Type: GrantFiled: November 21, 1996Date of Patent: August 17, 1999Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Kouji Kitagawa, Kouji Mizuishi, Masahiko Urano, Kenji Araki, Eiichi Iino, Izumi Fusegawa
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Patent number: 5938836Abstract: This invention provides an apparatus and a method for manufacturing semiconductor single crystals, which enable a steady process of pulling up high-quality single silicon crystals to be easily performed during the growing of silicon single crystals by the CZ method aided by applying a Cusp magnetic field. Three facing homopolar magnets (hereinafter referred to as magnet) 1, 2, and 3 arc disposed outside the single-crystal pulling up chamber. The magnet 3 is located at the same height as the free surface of the melt 6 stored in a quartz crucible as the free surface of the melt 6 stored in a quartz crucible 5. Furthermore, the strength of the magnets 3 is set to be weaker than that of the magnets 1 and 2. The flux lines of the magnets 3 substantially pass through the quartz crucible 5 in the horizontal direction. However, the flux lines of the magnet 3 do not reach the silicon single crystal 7 being pulled up.Type: GrantFiled: October 23, 1997Date of Patent: August 17, 1999Assignee: Komatsu Electronic Metals Co., Ltd.Inventors: Junsuke Tomioka, Hiroshi Inagaki, Katsura Yamamoto
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Patent number: 5911823Abstract: A method for pulling a <110> single-crystal silicon aims at preventing the crystal from being cut in diameter-reducing and suppress the increase in cost due to the cut prevention to the minimum. In the step for forming a diameter-reduced portion performed prior to the step for growing a <110> single-crystal silicon by the Czochralski method, a magnetic field having a strength of 500 gauss or more is applied and while suppressing a melt surface vibration and temperature variation, the crystal diameter is reduced to 2.00 mm or smaller.Type: GrantFiled: December 10, 1996Date of Patent: June 15, 1999Assignee: Komatsu Electronics Metals Co., Ltd.Inventors: Kouji Sonoda, Toshio Mimura
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Patent number: 5891245Abstract: A single crystal pulling method employing; a gas tight container, a double crucible for storing a semiconductor melt inside the gas tight container comprising an inter-connected outer crucible and inner crucible, and a source material supply tube suspended from an upper portion of the gas tight container and positioned so that a granulated or powdered source material can be added from a lower end opening thereof to the semiconductor melt inside the outer crucible, with the source material being injected into the source material supply tube together with an inert gas flowing towards the enclosed container, characterized in that said source material is injected under conditions where the flow rate N (1/min.multidot.cm.sup.2) of the inert gas is within the range 0.0048P+0.0264<N<0.07P, where P (Torr) is the internal pressure inside said gas tight container.Type: GrantFiled: January 10, 1997Date of Patent: April 6, 1999Assignees: Mitsubishi Materials Sillcon Corporation, Mitsubishi Materials CorporationInventors: Takashi Atami, Hiroaki Taguchi, Hisashi Furuya, Michio Kida
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Patent number: 5887015Abstract: A heater mechanism for a crystal pulling apparatus is disclosed. Electrodes made of copper or the like and disposed under a heater are connected to the heater via graphite members. A cover member is attached to each graphite member, so that the downwardly extending portion of the cover member surrounds the outer surface of the graphite member. Accordingly, a leak or splash of a melt is prevented from contacting the electrodes. The length of each graphite member is equal to or greater than the distance between the bottom surface of the heater and the top surface of a melt spill tray which distance is measured when the heater mechanism is raised The cover member is vertically slidable along the outer surface of each graphite member. Thus, even when a material melt leaks out from a crucible, the electrodes of the heater mechanism can be protected from a fusion damage or the like which would be otherwise caused by the leak of the melt.Type: GrantFiled: December 11, 1996Date of Patent: March 23, 1999Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Nobuaki Mitamura, Toshiharu Uesugi, Atsushi Iwasaki, Shinobu Takeyasu
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Patent number: 5882398Abstract: A single crystal of silicon is manufactured in accordance with the Czochralski method. A magnetic field is applied to a quartz crucible filled with silicon melt. Subsequently, a single crystal of silicon is pulled in a state in which no magnetic field is applied to the crucible, so as to obtain a single crystal of silicon. Therefore, the inner surface of a quartz crucible becomes very unlikely to deteriorate, and when the inner surface deteriorates, the deteriorated inner surface is restored. Accordingly, it is possible to manufacture a single crystal of silicon having a large diameter without generating a dislocation in the crystal. Moreover, even when a single crystal of silicon having a large diameter is manufactured, a larger number of single crystals of silicon can be manufactured from a single quartz crucible, and the pulling apparatus can be operated over a longer period of time using a single quartz crucible, thereby making it possible to manufacture a longer single crystal.Type: GrantFiled: January 23, 1997Date of Patent: March 16, 1999Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Susumu Sonokawa, Toshiro Hayashi, Atsushi Iwasaki, Tomohiko Ohta
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Patent number: 5879449Abstract: Homogeneous crystals are grown from a multicomponent melt double crucible assembly with an injector which affords improved flow of melt from the outer to the inner crucible. Guide rods are provided external to the outer crucible and locate the inner crucible with reduced probability of sticking. Means are also provided for withdrawing the inner crucible after crystal growth is complete as is a method of removing trapped gas from the apparatus prior to crystal growth.Type: GrantFiled: December 20, 1996Date of Patent: March 9, 1999Assignee: The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern IrelandInventor: John Alfred Beswick
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Patent number: 5871578Abstract: Oscillation of a growing crystal is suppressed in a Czochralski method when part of the growing crystal is mechanically held. Methods for holding and pulling a single crystal in a Czochralski method, wherein a seed crystal is pulled while rotating after the seed crystal is contacted with a raw material melt, part of the growing single crystal is mechanically held during pulling and the single crystal of heavy weight can be pulled regardless of mechanical strengths of the seed crystal or a neck portion thereof, wherein the raw material melt is under application of a magnetic field thereto when the growing crystal is mechanically held.Type: GrantFiled: August 20, 1997Date of Patent: February 16, 1999Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Eiichi Iino, Makoto Iida, Masanori Kimura, Shozo Muraoka
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Patent number: 5863326Abstract: The invention is directed to an apparatus, system and methods for growing high-purity crystals of substances that are peritectic at atmospheric pressure using the Czochralski technique. The apparatus includes a pressure vessel that contains a pressurized gas. The apparatus also includes a cooling unit that is situated in the pressure vessel. The cooling unit receives a coolant flow from outside of the vessel, and has cooled surfaces that define an enclosure that receives the charge material. The apparatus further includes an inductive heating element situated in the vessel, that is coupled to receive electric power externally to the vessel. The element heats the interior portion of the charge material to form a molten interior portion contained by a relatively cool, exterior solid-phase portion of the charge material that is closer relative to the molten interior, to the cooled surfaces of the cooling unit.Type: GrantFiled: March 14, 1997Date of Patent: January 26, 1999Assignee: Cermet, Inc.Inventors: Jeffrey E. Nause, D. Norman Hill, Stephen G. Pope