Patents by Inventor Isaho Kamata

Isaho Kamata 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).

  • Publication number: 20240110308
    Abstract: Provided are a method for manufacturing a silicon carbide single crystal, which can suppress conversion of threading edge dislocations into prismatic plane dislocations and conversion of the prismatic plane dislocations into basal plane dislocations; and a silicon carbide single crystal ingot and a silicon carbide wafer, in which conversion from threading edge dislocations into prismatic plane dislocations and conversion from the prismatic plane dislocations into basal plane dislocations have been suppressed. A silicon carbide single crystal is grown on the surface of a seed substrate by a gas method so that a temperature gradient in the radial direction of the seed substrate takes a predetermined value or lower during the growth.
    Type: Application
    Filed: September 15, 2023
    Publication date: April 4, 2024
    Inventors: Kiyoshi BETSUYAKU, Norihiro HOSHINO, Isaho KAMATA, Hidekazu TSUCHIDA, Takeshi OKAMOTO, Takahiro KANDA
  • Publication number: 20240110309
    Abstract: Provided are a method for manufacturing a silicon carbide single crystal, and a silicon carbide single crystal ingot which ensure a high crystal growth rate and increase the ratio of conversion from basal plane dislocations to threading edge dislocations. The method prepares a seed substrate composed of silicon carbide having an off-angle in a [1-100] direction with respect to a {0001} plane; and grows a silicon carbide single crystal layer on the seed substrate by an HTCVD method, thereby converting basal plane dislocations contained in the seed substrate to threading edge dislocations during crystal growth.
    Type: Application
    Filed: September 29, 2023
    Publication date: April 4, 2024
    Inventors: Kiyoshi BETSUYAKU, Norihiro HOSHINO, Isaho KAMATA, Hidekazu TSUCHIDA, Akiyoshi HORIAI, Takeshi OKAMOTO
  • Patent number: 11906569
    Abstract: A semiconductor wafer evaluation apparatus brings a contact maker (mercury liquefied at room temperature), as a Schottky electrode, into contact with a semiconductor wafer, intermittently applies a voltage from a pulse power supply, and evaluates the state (kinds, density) of point defects by an evaluation means based on the status of the electrostatic capacity of the semiconductor wafer. In this manner, the state (kinds, density) of the point defects in the plane of a large-diameter semiconductor wafer is directly evaluated using a large table.
    Type: Grant
    Filed: November 5, 2021
    Date of Patent: February 20, 2024
    Assignee: SHOWA DENKO K.K.
    Inventors: Koichi Murata, Isaho Kamata, Hidekazu Tsuchida, Akira Miyasaka
  • Patent number: 11846040
    Abstract: A silicon carbide single crystal contains a heavy metal element having a specific gravity higher than a specific gravity of iron. An addition density of the heavy metal element at least in an outer peripheral portion of the silicon carbide single crystal is set to 1×1015 cm?3 or more.
    Type: Grant
    Filed: December 16, 2020
    Date of Patent: December 19, 2023
    Assignees: DENSO CORPORATION, CENTRAL RESEARCH INSTITUTE OF ELECTRIC POWER INDUSTRY
    Inventors: Yuichiro Tokuda, Hideyuki Uehigashi, Norihiro Hoshino, Hidekazu Tsuchida, Isaho Kamata
  • Publication number: 20230374699
    Abstract: A raw material gas is supplied to a space in which a silicon carbide seed crystal is placed. A silicon carbide single crystal is grown on the seed crystal by keeping a monosilane partial pressure at 4 kPa or more and heating the space to a temperature of 2400° C. to 2700° C. The temperature of the space and supply of the raw material gas are controlled such that a temperature gradient of a growth crystal surface of the silicon carbide single crystal in a radial direction is 0.1° C./mm or less, and a radius of curvature of the growth crystal surface is 4.5 m or more, thereby producing a silicon carbide single crystal ingot having a growth length of 3 mm or more and an internal stress of 10 MPa or less. The ingot is then cut into a silicon carbide single crystal wafer.
    Type: Application
    Filed: July 31, 2023
    Publication date: November 23, 2023
    Inventors: Isaho KAMATA, Hidekazu TSUCHIDA, Norihiro HOSHINO, Yuichiro TOKUDA, Takeshi OKAMOTO
  • Publication number: 20230279580
    Abstract: A manufacturing method of a silicon carbide single crystal includes growing the silicon carbide single crystal on a surface of a seed crystal by supplying a supply gas including a raw material gas of silicon carbide to the surface of the seed crystal and controlling an environment so that at least a part inside the heating vessel is 2500° C. or higher. The growing the silicon carbide single crystal includes controlling a temperature distribution ?T in a radial direction centering on central axis of the seed crystal and the silicon carbide single crystal satisfies a radial direction temperature condition of ?T?10° C. on the surface of the seed crystal before the growing of the silicon carbide single crystal and on a growth surface of the silicon carbide single crystal during the growing of the silicon carbide single crystal.
    Type: Application
    Filed: January 30, 2023
    Publication date: September 7, 2023
    Inventors: Akiyoshi HORIAI, Takeshi OKAMOTO, Takahiro KANDA, Norihiro HOSHINO, Kiyoshi BETSUYAKU, Isaho KAMATA, Hidekazu TSUCHIDA, Takashi KANEMURA
  • Publication number: 20230193510
    Abstract: A silicon carbide ingot having micropipes in a seed crystal closed and being reduced in the gathering of screw dislocations, a method for manufacturing the silicon carbide ingot, and a method for manufacturing a silicon carbide wafer are provided. The silicon carbide ingot comprises: a seed crystal composed of a silicon carbide single crystal and having micropipes being hollow defects; a buffer layer provided on the seed crystal and composed of silicon carbide; and a bulk crystal growth layer provided on the buffer layer and composed of silicon carbide. The buffer layer and the bulk crystal growth layer have a plurality of screw dislocations continuous with the micropipes closed with the buffer layer, and the plurality of screw dislocations having the micropipe in common in the bulk crystal growth layer are 150 ?m or more apart from each other.
    Type: Application
    Filed: November 30, 2022
    Publication date: June 22, 2023
    Inventors: Isaho KAMATA, Norihiro HOSHINO, Kiyoshi BETSUYAKU, Hidekazu TSUCHIDA, Takeshi OKAMOTO, Akiyoshi HORIAI
  • Publication number: 20220146564
    Abstract: A semiconductor wafer evaluation apparatus brings a contact maker (mercury liquefied at room temperature), as a Schottky electrode, into contact with a semiconductor wafer, intermittently applies a voltage from a pulse power supply, and evaluates the state (kinds, density) of point defects by an evaluation means based on the status of the electrostatic capacity of the semiconductor wafer. In this manner, the state (kinds, density) of the point defects in the plane of a large-diameter semiconductor wafer is directly evaluated using a large table.
    Type: Application
    Filed: November 5, 2021
    Publication date: May 12, 2022
    Applicant: SHOWA DENKO K.K.
    Inventors: Koichi Murata, Isaho KAMATA, Hidekazu TSUCHIDA, Akira MIYASAKA
  • Publication number: 20220112623
    Abstract: A method and an apparatus for manufacturing a silicon carbide single crystal, and a silicon carbide single crystal ingot, obtaining a silicon carbide single crystal reduced in defects such as threading dislocations, are provided. The method manufactures a silicon carbide single crystal by supplying a raw material gas into a reaction vessel with a seed substrate, and heats the interior to grow a silicon carbide single crystal on the surface of the seed substrate. The method includes growing the silicon carbide single crystal on the seed substrate surface, while controlling the temperature, to perform pair annihilation of threading dislocations or synthesis of the threading dislocations; and a second step of maintaining the temperature inside the reaction vessel in the state of the first predetermined temperature after execution of the first step, to bring the leading ends of the threading dislocations close to the surface of the seed substrate.
    Type: Application
    Filed: October 12, 2021
    Publication date: April 14, 2022
    Inventors: Norihiro HOSHINO, Isaho KAMATA, Hidekazu TSUCHIDA, Takahiro KANDA, Takeshi OKAMOTO
  • Patent number: 11107892
    Abstract: A method for producing a SiC epitaxial wafer according to the present embodiment includes: an epitaxial growth step of growing the epitaxial layer on the SiC single crystal substrate by feeding an Si-based raw material gas, a C-based raw material gas, and a gas including a Cl element to a surface of a SiC single crystal substrate, in which the epitaxial growth step is performed under growth conditions that a film deposition pressure is 30 torr or less, a Cl/Si ratio is in a range of 8 to 12, a C/Si ratio is in a range of 0.8 to 1.2, and a growth rate is 50 ?m/h or more from an initial growth stage.
    Type: Grant
    Filed: April 19, 2018
    Date of Patent: August 31, 2021
    Assignees: SHOWA DENKO K.K., Central Research Institute Of Electric Power Industry, DENSO CORPORATION
    Inventors: Keisuke Fukada, Naoto Ishibashi, Akira Bando, Masahiko Ito, Isaho Kamata, Hidekazu Tsuchida, Kazukuni Hara, Masami Naito, Hideyuki Uehigashi, Hiroaki Fujibayashi, Hirofumi Aoki, Toshikazu Sugiura, Katsumi Suzuki
  • Publication number: 20210108334
    Abstract: In a silicon carbide single crystal wafer, a dislocation density contained therein is 3500 dislocations/cm2 or less, and a difference of the dislocation density among a wafer central part, a wafer peripheral part and a wafer intermediate part is less than 50% of an average value thereof.
    Type: Application
    Filed: September 22, 2020
    Publication date: April 15, 2021
    Inventors: Isaho KAMATA, Hidekazu TSUCHIDA, Norihiro HOSHINO, Yuichiro TOKUDA, Takeshi OKAMOTO
  • Publication number: 20210102311
    Abstract: A silicon carbide single crystal contains a heavy metal element having a specific gravity higher than a specific gravity of iron. An addition density of the heavy metal element at least in an outer peripheral portion of the silicon carbide single crystal is set to 1×1015 cm?3 or more.
    Type: Application
    Filed: December 16, 2020
    Publication date: April 8, 2021
    Inventors: Yuichiro TOKUDA, Hideyuki UEHIGASHI, Norihiro HOSHINO, Hidekazu TSUCHIDA, Isaho KAMATA
  • Patent number: 10896831
    Abstract: A supply part includes a first partition, a second partition under the first partition, a third partition under the second partition, a first flow path between the first partition and the second partition allowing a first gas to be introduced therein, a second flow path between the second partition and the third partition allowing a second gas to be introduced therein, a first piping extending from the second partition to reach below the third partition and being communicated with the first flow path, a second piping extending from the third partition to reach below the third partition and being communicated with the second flow path, and a convex portion provided on an outer circumferential surface of the first piping or an inner circumferential surface of the second piping protruding from one of the outer circumferential surface and the inner circumferential surface toward the other one.
    Type: Grant
    Filed: August 31, 2018
    Date of Patent: January 19, 2021
    Assignees: NuFlare Technology, Inc., Showa Denko K.K., Central Research Institute of Electric Power Industry
    Inventors: Kunihiko Suzuki, Naohisa Ikeya, Keisuke Fukada, Masahiko Ito, Isaho Kamata, Hidekazu Tsuchida, Hiroaki Fujibayashi, Hideyuki Uehigashi, Masami Naito, Kazukuni Hara, Hirofumi Aoki, Takahiro Kozawa
  • Publication number: 20200083330
    Abstract: A method for producing a SiC epitaxial wafer according to the present embodiment includes: an epitaxial growth step of growing the epitaxial layer on the SiC single crystal substrate by feeding an Si-based raw material gas, a C-based raw material gas, and a gas including a Cl element to a surface of a SiC single crystal substrate, in which the epitaxial growth step is performed under growth conditions that a film deposition pressure is 30 torr or less, a Cl/Si ratio is in a range of 8 to 12, a C/Si ratio is in a range of 0.8 to 1.2, and a growth rate is 50 ?m/h or more from an initial growth stage.
    Type: Application
    Filed: April 19, 2018
    Publication date: March 12, 2020
    Applicants: SHOWA DENKO K.K., Central Research Institute of Electric Power Industry, DENSO CORPORATION
    Inventors: Keisuke FUKADA, Naoto ISHIBASHI, Akira BANDO, Masahiko ITO, Isaho KAMATA, Hidekazu TSUCHIDA, Kazukuni HARA, Masami NAITO, Hideyuki UEHIGASHI, Hiroaki FUJIBAYASHI, Hirofumi AOKI, Toshikazu SUGIURA, Katsumi SUZUKI
  • Patent number: 10584417
    Abstract: A film forming apparatus according to an embodiment of the invention includes: a film forming chamber configured to form a film on a substrate; a susceptor configured to place the substrate thereon; a rotating part configured to rotate the susceptor; a heater configured to heat the substrate; and a gas supplier configured to supply process gases into the film forming chamber, wherein the susceptor includes: a ring-shaped outer circumferential susceptor supported by the rotating part; a holder provided at an inner circumferential portion of the outer circumferential susceptor, the holder configured to hold the substrate; a ring-shaped plate provided over the outer circumferential susceptor; and a cover member configured to cover a top surface and an outer circumferential surface of the plate and an outer circumferential surface of the outer circumferential susceptor.
    Type: Grant
    Filed: July 10, 2015
    Date of Patent: March 10, 2020
    Assignee: NuFlare Technology, Inc.
    Inventors: Hideki Ito, Hidekazu Tsuchida, Isaho Kamata, Masahiko Ito, Masami Naito, Hiroaki Fujibayashi, Katsumi Suzuki, Koichi Nishikawa
  • Publication number: 20190376206
    Abstract: This SiC epitaxial wafer includes: a SiC single crystal substrate of which a main surface has an off-angle of 0.4° to 5° with respect to (0001) plane; and an epitaxial layer provided on the SiC single crystal substrate, wherein the epitaxial layer has a basal plane dislocation density of 0.1 pieces/cm2 or less that is a density of basal plane dislocations extending from the SiC single crystal substrate to an outer surface and an intrinsic 3C triangular defect density of 0.1 pieces/cm2 or less.
    Type: Application
    Filed: December 25, 2017
    Publication date: December 12, 2019
    Applicants: SHOWA DENKO K.K, Central Research Institute of Electric Power Industry, DENSO CORPORATION
    Inventors: Keisuke FUKADA, Naoto ISHIBASHI, Akira BANDO, Masahiko ITO, Isaho KAMATA, Hidekazu TSUCHIDA, Kazukuni HARA, Masami NAITO, Hideyuki UEHIGASHI, Hiroaki FUJIBAYASHI, Hirofumi AOKI, Toshikazu SUGIURA, Katsumi SUZUKI
  • Patent number: 10262863
    Abstract: A method for manufacturing a SiC epitaxial wafer according to one aspect of the present invention includes separately introducing, into a reaction space for SiC epitaxial growth, a basic N-based gas composed of molecules containing an N atom within the molecular structure but having neither a double bond nor a triple bond between nitrogen atoms, and a Cl-based gas composed of molecules containing a Cl atom within the molecular structure, and mixing the N-based gas and the Cl-based gas at a temperature equal to or higher than the boiling point or sublimation temperature of a solid product generated by mixing the N-based gas and the Cl-based gas.
    Type: Grant
    Filed: December 8, 2015
    Date of Patent: April 16, 2019
    Assignees: SHOWA DENKO K.K., Central Research Institute Of Electric Power Industry
    Inventors: Keisuke Fukada, Masahiko Ito, Isaho Kamata, Hidekazu Tsuchida, Hideyuki Uehigashi, Hiroaki Fujibayashi, Masami Naito, Kazukuni Hara, Takahiro Kozawa, Hirofumi Aoki
  • Patent number: 10181517
    Abstract: A silicon carbide single crystal includes: threading dislocations each of which having a dislocation line extending through a C-plane, and a Burgers vector including at least a component in a C-axis direction. In addition, a density of the threading dislocations having angles, each of which is formed by an orientation of the Burgers vector and an orientation of the dislocation line, larger than 0° and within 40° is set to 300 dislocations/cm2 or less. Furthermore, a density of the threading dislocations having the angles larger than 40° is set to 30 dislocations/cm2 or less.
    Type: Grant
    Filed: August 25, 2016
    Date of Patent: January 15, 2019
    Assignee: DENSO CORPORATION
    Inventors: Takeshi Okamoto, Hiroyuki Kondo, Takashi Kanemura, Shinichiro Miyahara, Yasuhiro Ebihara, Shoichi Onda, Hidekazu Tsuchida, Isaho Kamata, Ryohei Tanuma
  • Publication number: 20180374721
    Abstract: A supply part includes a first partition, a second partition under the first partition, a third partition under the second partition, a first flow path between the first partition and the second partition allowing a first gas to be introduced therein, a second flow path between the second partition and the third partition allowing a second gas to be introduced therein, a first piping extending from the second partition to reach below the third partition and being communicated with the first flow path, a second piping extending from the third partition to reach below the third partition and being communicated with the second flow path, and a convex portion provided on an outer circumferential surface of the first piping or an inner circumferential surface of the second piping protruding from one of the outer circumferential surface and the inner circumferential surface toward the other one.
    Type: Application
    Filed: August 31, 2018
    Publication date: December 27, 2018
    Inventors: Kunihiko Suzuki, Naohisa Ikeya, Keisuke Fukada, Masahiko Ito, Isaho Kamata, Hidekazu Tsuchida, Hiroaki Fujibayashi, Hideyuki Uehigashi, Masami Naito, Kazukuni Hara, Hirofumi Aoki, Takahiro Kozawa
  • Publication number: 20180219069
    Abstract: A silicon carbide single crystal includes: threading dislocations each of which having a dislocation line extending through a C-plane, and a Burgers vector including at least a component in a C-axis direction. In addition, a density of the threading dislocations having angles, each of which is formed by an orientation of the Burgers vector and an orientation of the dislocation line, larger than 0° and within 40° is set to 300 dislocations/cm2 or less. Furthermore, a density of the threading dislocations having the angles larger than 40° is set to 30 dislocations/cm2 or less.
    Type: Application
    Filed: August 25, 2016
    Publication date: August 2, 2018
    Inventors: Takeshi OKAMOTO, Hiroyuki KONDO, Takashi KANEMURA, Shinichiro MIYAHARA, Yasuhiro EBIHARA, Shoichi ONDA, Hidekazu TSUCHIDA, Isaho KAMATA, Ryohei TANUMA