Patents by Inventor Ryoji Hoshi
Ryoji Hoshi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20050211158Abstract: There are disclosed a silicon wafer for epitaxial growth wherein the wafer is produced by slicing a silicon single crystal grown with doping nitrogen according to the Czochralski method (CZ method) in the region where at least the center of the wafer becomes V region in which the void type defects are generated, and wherein the number of defects having an opening size of 20 nm or less among the void type defects appearing on the surface of the wafer is 0.02/cm2 or less, and an epitalial wafer wherein an epitaxial layer is formed on the silicon wafer for epitaxial growth. Thereby, there can be produced an epitaxial wafer having a high gettering capability wherein very few SF exist in the epitaxial layer easily at high productivity and at low cost.Type: ApplicationFiled: July 8, 2003Publication date: September 29, 2005Applicant: Shin-Etsu Handotai Co., Ltd.Inventors: Ryoji Hoshi, Susumu Sonokawa
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Patent number: 6893499Abstract: According to the present invention, there is disclosed a silicon single crystal wafer grown according to the CZ method which is a wafer having a diameter of 200 mm or more produced from a single crystal grown at a growth rate of 0.5 mm/min or more without doping except for a dopant for controlling resistance, wherein neither an octahedral void defect due to vacancies nor a dislocation cluster due to interstitial silicons exists as a grown-in defect, and a method for producing it.Type: GrantFiled: June 28, 2001Date of Patent: May 17, 2005Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Izumi Fusegawa, Koji Kitagawa, Ryoji Hoshi, Masahiro Sakurada, Tomohiko Ohta
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Publication number: 20050081779Abstract: The present invention provides a heater for manufacturing a crystal by the Czochralski method comprising at least terminal portions supplied with current and a heat generating portion by resistance heating, and being arranged so as to surround a crucible containing a raw material melt, wherein the heater has a uniform heat generation distribution to the raw material melt after deformation while in use during crystal manufacture. It is thus possible to prevent hindrance of monocrystallization and unstable crystal quality caused by ununiform temperature in the raw material melt due to deformation of the shape of the heater's heat generating portion while in use during crystal manufacture.Type: ApplicationFiled: September 8, 2003Publication date: April 21, 2005Inventors: Susumu Sonokawa, Ryoji Hoshi, Wataru Sato, Tomohiko Ohta
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Patent number: 6764548Abstract: The present invention provides an apparatus and a method for producing a silicon semiconductor single crystal which can stabilize and homogenize an amount of precipitated oxygen in the direction of the crystal growth axis when growing a silicon semiconductor single crystal. The apparatus for producing a silicon semiconductor single crystal by the Czochralski method comprises a main growth furnace having a crucible retaining silicon melt disposed therein for growing a silicon semiconductor single crystal, and an upper growth furnace for housing therein and cooling the silicon semiconductor single crystal pulled from the silicon melt, wherein the upper growth furnace communicated to a ceiling section of the main growth furnace is provided with an upper insulating member for surrounding a pulled silicon semiconductor single crystal.Type: GrantFiled: August 20, 2002Date of Patent: July 20, 2004Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Ryoji Hoshi, Takahiro Yanagimachi, Izumi Fusegawa, Tomohiko Ohta, Yuuichi Miyahara, Tetsuya Igarashi
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Patent number: 6632280Abstract: An apparatus for growing a single crystal (20) comprising at least a main chamber (1) enclosing a crucible (5, 6) for accommodating a raw material melt (4) and a heater (7) for heating the raw material melt and a pulling chamber (2) continuously provided above the main chamber, into which a grown single crystal is pulled and stored, wherein the apparatus further comprises a cooling cylinder (11) that extends at least from a ceiling of the main chamber toward a raw material melt surface so as to surround a single crystal under pulling (3) and is forcibly cooled with a cooling medium, and an auxiliary cooling member (13) extending below the cooling cylinder and having a cylindrical shape or a shape tapered toward the downward direction. There is provided an apparatus for growing a single crystal that can exert cooling effect on a grown single crystal to the maximum extent so as to accelerate the crystal growth rate and safely produce a single crystal without leakage of cooling medium due to breakage etc.Type: GrantFiled: September 21, 2001Date of Patent: October 14, 2003Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Ryoji Hoshi, Koji Kitagawa, Izumi Fusegawa, Tomohiko Ohta
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Patent number: 6632411Abstract: The present invention provides a silicon wafer sliced from a silicon single crystal ingot grown by the Czochralski method under such conditions that V-rich region should become dominant, wherein count number of particles having a size of 0.1 &mgr;m or more is 1 count/cm2 or less when particles are counted by using a particle counter and a method for producing a silicon single crystal. Thus, there is provided a production technique that can improve productivity and reduce cost for high quality silicon wafers of excellent device characteristics by further reducing density and size of defects such as COP.Type: GrantFiled: November 23, 2001Date of Patent: October 14, 2003Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Ryoji Hoshi, Izumi Fusegawa, Tomohiko Ohta, Shigemaru Maeda
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Patent number: 6592662Abstract: 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: GrantFiled: October 24, 2001Date of Patent: July 15, 2003Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Izumi Fusegawa, Ryoji Hoshi, Kouichi Inokoshi, Tomohiko Ohta
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Publication number: 20030106484Abstract: According to the present invention, there is disclosed a silicon single crystal wafer grown according to the CZ method which is a wafer having a diameter of 200 mm or more produced from a single crystal grown at a growth rate of 0.5 mm/min or more without doping except for a dopant for controlling resistance, wherein neither an octahedral void defect due to vacancies nor a dislocation cluster due to interstitial silicons exists as a grown-in defect, and a method for producing it.Type: ApplicationFiled: December 26, 2002Publication date: June 12, 2003Inventors: Izumi Fusegawa, Koji Kitagawa, Ryoji Hoshi, Masahiro Sakurada, Tomohiko Ohta
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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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Publication number: 20030089300Abstract: The present invention provides an apparatus and a method for producing a silicon semiconductor single crystal which can stabilize and homogenize an amount of precipitated oxygen in the direction of the crystal growth axis when growing a silicon semiconductor single crystal. The apparatus for producing a silicon semiconductor single crystal by the Czochralski method comprises a main growth furnace having a crucible retaining silicon melt disposed therein for growing a silicon semiconductor single crystal, and an upper growth furnace for housing therein and cooling the silicon semiconductor single crystal pulled from the silicon melt, wherein the upper growth furnace communicated to a ceiling section of the main growth furnace is provided with an upper insulating member for surrounding a pulled silicon semiconductor single crystal.Type: ApplicationFiled: August 20, 2002Publication date: May 15, 2003Inventors: Ryoji Hoshi, Takahiro Yanagimachi, Izumi Fusegawa, Tomohiko Ohta, Yuuichi Miyahara, Tetsuya Igarashi
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Publication number: 20030070605Abstract: An apparatus for growing a single crystal (20) comprising at least a main chamber (1) enclosing a crucible (5, 6) for accommodating a raw material melt (4) and a heater (7) for heating the raw material melt and a pulling chamber (2) continuously provided above the main chamber, into which a grown single crystal is pulled and stored, wherein the apparatus further comprises a cooling cylinder (11) that extends at least from a ceiling of the main chamber toward a raw material melt surface so as to surround a single crystal under pulling (3) and is forcibly cooled with a cooling medium, and an auxiliary cooling member (13) extending below the cooling cylinder and having a cylindrical shape or a shape tapered toward the downward direction. There is provided an apparatus for growing a single crystal that can exert cooling effect on a grown single crystal to the maximum extent so as to accelerate the crystal growth rate and safely produce a single crystal without leakage of cooling medium due to breakage etc.Type: ApplicationFiled: September 21, 2001Publication date: April 17, 2003Inventors: Ryoji Hoshi, Koji Kitagawa, Izumi Fusegawa, Tomohiko Ohta
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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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Publication number: 20020157598Abstract: The present invention provides a silicon wafer sliced from a silicon single crystal ingot grown by the Czochralski method under such conditions that V-rich region should become dominant, wherein count number of particles having a size of 0.1 &mgr;m or more is 1 count/cm2 or less when particles are counted by using a particle counter and a method for producing a silicon single crystal. Thus, there is provided a production technique that can improve productivity and reduce cost for high quality silicon wafers of excellent device characteristics by further reducing density and size of defects such as COP.Type: ApplicationFiled: November 23, 2001Publication date: October 31, 2002Inventors: Ryoji Hoshi, Izumi Fusegawa, Tomohiko Ohta, Shigemaru Maeda
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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: 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: 5612539Abstract: A lifetime related quality evaluation method, used with a semiconductor wafer having a semiconductor thin layer over the main surface of a semiconductor substrate, for evaluating the lifetime related quality of the semiconductor thin layer and/or the vicinity thereof, characterized by: generating electron-hole pairs in the vicinity of a surface of the semiconductor thin layer by the use of excitation light having a larger energy than the band gap of a semiconductor to be tested; then detecting the intensity at a particular wavelength of light emitted by recombination of the electron-hole pairs; and evaluating the lifetime related quality of the semiconductor thin layer and/or the vicinity thereof based on the detected intensity. The lifetime related quality evaluation method realizes a non-contact, non-destructive quality evaluation of the epitaxial semiconductor wafer.Type: GrantFiled: November 14, 1995Date of Patent: March 18, 1997Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Ryoji Hoshi, Yutaka Kitagawara, Takao Takenaka
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Patent number: 5598452Abstract: According to the invention, it is sought to provide a method of evaluating single crystal of silicon, which permits determination of the amount of precipitated oxygen of even a sample having been heat treated and with unknown initial interstitial oxygen concentration. X-rays radiated from X-ray source 7 is converted by slit 6 into a thin, parallel incident X-ray beam 3 to be incident on sample single crystal 1. After adjusting the angle .theta.1 of sample with respect to the incident X-ray beam such as to satisfy Bragg conditions, diffracted X-rays 4 produced by diffraction on the sample single crystal 1 are coupled from the back side thereof through X-ray receiving slit 8 to scintillator 5 for intensity measurement. The amount of precipitated oxygen is calculated from the measured diffracted X-ray intensity.Type: GrantFiled: September 6, 1995Date of Patent: January 28, 1997Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Hiroshi Takeno, Ryoji Hoshi, Satoshi Ushio, Takao Takenaka
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Patent number: 5302832Abstract: Spatial distribution of deep level concentration near the surface of a semiconductor wafer is evaluated quickly and accurately by a method which comprises at least a step of scanning the surface of the semiconductor wafer in the X and Y direction with a laser beam for carrier excitation from a laster beam source in accordance with the room-temperature photoluminescence (PL) process thereby measuring the wafer map (M.sub.D) of deep level PL intensity (I.sub.D) and wafer map (M.sub.B) of band edge PL intensity (I.sub.B) in the semiconductor wafer and a step of dividing the wafer map (M.sub.D) of PL intensity (I.sub.D) by the .nu.'th power of the wafer map (M.sub.B) of PL intensity (I.sub.B) {the magnitude of the .nu.'th power presenting the numerical value obtained by empirically confirming the dependence of the band edge PL intensity (I.sub.B) on the power of the excitation laster mean} thereby determining the spatial distribution (M.sub.N) of the relative value of deep level concentration (N.sub.Type: GrantFiled: September 25, 1992Date of Patent: April 12, 1994Assignee: Shin-Etsu Handotai Co., Ltd.Inventors: Yutaka Kitagawara, Ryoji Hoshi, Takao Takenaka