Patents by Inventor Hiroshi TAKISHITA

Hiroshi TAKISHITA 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).

  • Patent number: 10199453
    Abstract: Proton irradiation is performed a plurality of times from rear surface of an n-type semiconductor substrate, which is an n? drift layer, forming an n-type FS layer having lower resistance than the n-type semiconductor substrate in the rear surface of the n? drift layer. When the proton irradiation is performed a plurality of times, the next proton irradiation is performed to as to compensate for a reduction in mobility due to disorder which remains after the previous proton irradiation. In this case, the second or subsequent proton irradiation is performed at the position of the disorder which is formed by the previous proton irradiation. In this way, even after proton irradiation and a heat treatment, the disorder is reduced and it is possible to prevent deterioration of characteristics, such as increase in leakage current. It is possible to form an n-type FS layer including a high-concentration hydrogen-related donor layer.
    Type: Grant
    Filed: July 25, 2018
    Date of Patent: February 5, 2019
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Hiroshi Takishita, Takashi Yoshimura, Masayuki Miyazaki, Hidenao Kuribayashi
  • Publication number: 20180350901
    Abstract: Hydrogen atoms and crystal defects are introduced into an n-semiconductor substrate by proton implantation. The crystal defects are generated in the n-semiconductor substrate by electron beam irradiation before or after the proton implantation. Then, a heat treatment for generating donors is performed. The amount of crystal defects is appropriately controlled during the heat treatment for generating donors to increase a donor generation rate. In addition, when the heat treatment for generating donors ends, the crystal defects formed by the electron beam irradiation and the proton implantation are recovered and controlled to an appropriate amount of crystal defects. Therefore, for example, it is possible to improve a breakdown voltage and reduce a leakage current.
    Type: Application
    Filed: July 30, 2018
    Publication date: December 6, 2018
    Inventors: Takashi YOSHIMURA, Masayuki MIYAZAKI, Hiroshi TAKISHITA, Hidenao KURIBAYASHI
  • Publication number: 20180331176
    Abstract: Proton irradiation is performed a plurality of times from rear surface of an n-type semiconductor substrate, which is an n? drift layer, forming an n-type FS layer having lower resistance than the n-type semiconductor substrate in the rear surface of the n? drift layer. When the proton irradiation is performed a plurality of times, the next proton irradiation is performed to as to compensate for a reduction in mobility due to disorder which remains after the previous proton irradiation. In this case, the second or subsequent proton irradiation is performed at the position of the disorder which is formed by the previous proton irradiation. In this way, even after proton irradiation and a heat treatment, the disorder is reduced and it is possible to prevent deterioration of characteristics, such as increase in leakage current. It is possible to form an n-type FS layer including a high-concentration hydrogen-related donor layer.
    Type: Application
    Filed: July 25, 2018
    Publication date: November 15, 2018
    Inventors: Hiroshi TAKISHITA, Takashi YOSHIMURA, Masayuki MIYAZAKI, Hidenao KURIBAYASHI
  • Patent number: 10128360
    Abstract: A method of producing a semiconductor device is disclosed in which, after proton implantation is performed, a hydrogen-induced donor is formed by a furnace annealing process to form an n-type field stop layer. A disorder generated in a proton passage region is reduced by a laser annealing process to form an n-type disorder reduction region. As such, the n-type field stop layer and the n-type disorder reduction region are formed by the proton implantation. Therefore, it is possible to provide a stable and inexpensive semiconductor device which has low conduction resistance and can improve electrical characteristics, such as a leakage current, and a method for producing the semiconductor device.
    Type: Grant
    Filed: December 11, 2017
    Date of Patent: November 13, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Masayuki Miyazaki, Takashi Yoshimura, Hiroshi Takishita, Hidenao Kuribayashi
  • Patent number: 10056449
    Abstract: Proton irradiation is performed a plurality of times from rear surface of an n-type semiconductor substrate, which is an n? drift layer, forming an n-type FS layer having lower resistance than the n-type semiconductor substrate in the rear surface of the n? drift layer. When the proton irradiation is performed a plurality of times, the next proton irradiation is performed to as to compensate for a reduction in mobility due to disorder which remains after the previous proton irradiation. In this case, the second or subsequent proton irradiation is performed at the position of the disorder which is formed by the previous proton irradiation. In this way, even after proton irradiation and a heat treatment, the disorder is reduced and it is possible to prevent deterioration of characteristics, such as increase in leakage current. It is possible to form an n-type FS layer including a high-concentration hydrogen-related donor layer.
    Type: Grant
    Filed: July 28, 2017
    Date of Patent: August 21, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Hiroshi Takishita, Takashi Yoshimura, Masayuki Miyazaki, Hidenao Kuribayashi
  • Patent number: 10056451
    Abstract: Hydrogen atoms and crystal defects are introduced into an n? semiconductor substrate by proton implantation. The crystal defects are generated in the n? semiconductor substrate by electron beam irradiation before or after the proton implantation. Then, a heat treatment for generating donors is performed. The amount of crystal defects is appropriately controlled during the heat treatment for generating donors to increase a donor generation rate. In addition, when the heat treatment for generating donors ends, the crystal defects formed by the electron beam irradiation and the proton implantation are recovered and controlled to an appropriate amount of crystal defects. Therefore, for example, it is possible to improve a breakdown voltage and reduce a leakage current.
    Type: Grant
    Filed: July 17, 2017
    Date of Patent: August 21, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Takashi Yoshimura, Masayuki Miyazaki, Hiroshi Takishita, Hidenao Kuribayashi
  • Patent number: 10050106
    Abstract: A p+ collector layer is provided in a rear surface of a semiconductor substrate which will be an n? drift layer and an n+ field stop layer is provided in a region which is deeper than the p+ collector layer formed on the rear surface side. A front surface element structure is formed on the front surface of the semiconductor substrate and then protons are radiated to the rear surface of the semiconductor substrate at an acceleration voltage corresponding to the depth at which the n+ field stop layer is formed. A first annealing process is performed at an annealing temperature corresponding to the proton irradiation to change the protons into donors, thereby forming a field stop layer. Then, annealing is performed using annealing conditions suitable for the conditions of a plurality of proton irradiation processes to recover each crystal defect formed by each proton irradiation process.
    Type: Grant
    Filed: June 3, 2016
    Date of Patent: August 14, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Masayuki Miyazaki, Takashi Yoshimura, Hiroshi Takishita, Hidenao Kuribayashi
  • Publication number: 20180175216
    Abstract: A semiconductor device includes first to fourth semiconductor regions, and first and second electrodes. The second semiconductor region is selectively disposed in a surface layer of one main surface of the first semiconductor region. The first electrode is in contact with a contact region of the second semiconductor region. The third semiconductor region is disposed in a surface layer on another main surface of the first semiconductor region, and having an impurity concentration higher than that of the first semiconductor region. The second electrode is in contact with the third semiconductor region. The fourth semiconductor region of the second conductivity type is disposed in the first semiconductor region, and disposed closer to the one main surface than the third semiconductor region. The fourth semiconductor region is disposed at least within the contact region in a plan view.
    Type: Application
    Filed: February 5, 2018
    Publication date: June 21, 2018
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Yuichi ONOZAWA, Takashi YOSHIMURA, Hiroshi TAKISHITA
  • Publication number: 20180108765
    Abstract: A method of producing a semiconductor device is disclosed in which, after proton implantation is performed, a hydrogen-induced donor is formed by a furnace annealing process to form an n-type field stop layer. A disorder generated in a proton passage region is reduced by a laser annealing process to form an n-type disorder reduction region. As such, the n-type field stop layer and the n-type disorder reduction region are formed by the proton implantation. Therefore, it is possible to provide a stable and inexpensive semiconductor device which has low conduction resistance and can improve electrical characteristics, such as a leakage current, and a method for producing the semiconductor device.
    Type: Application
    Filed: December 11, 2017
    Publication date: April 19, 2018
    Inventors: Masayuki MIYAZAKI, Takashi YOSHIMURA, Hiroshi TAKISHITA, Hidenao KURIBAYASHI
  • Patent number: 9893211
    Abstract: Provided is a semiconductor device manufacturing method. The device has a substrate including one and another surfaces. A first semiconductor region of a first conductivity type is formed in the substrate. A second conductivity type, second semiconductor region is provided in a first surface layer, that includes the one surface, of the substrate. A first electrode is in contact with the second semiconductor region to form a junction therebetween. A first conductivity type, third semiconductor region is provided in a second surface layer, that includes the another surface, of the substrate. The third semiconductor region has a higher impurity concentration than the first semiconductor region. A fourth semiconductor region of the second conductivity type is provided in the first semiconductor region at a location deeper than the third semiconductor region from the another surface. A second electrode is in contact with the third semiconductor region.
    Type: Grant
    Filed: August 24, 2017
    Date of Patent: February 13, 2018
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Yuichi Onozawa, Takashi Yoshimura, Hiroshi Takishita
  • Publication number: 20180005829
    Abstract: Provided is a semiconductor device including: a semiconductor substrate doped with an impurity; a front-surface-side electrode provided at a side of a front surface of the semiconductor substrate; and a back-surface-side electrode provided at a side of a back surface of the semiconductor substrate; wherein the semiconductor substrate includes: a peak region arranged at the side of the back surface of the semiconductor substrate and having one or more peaks of an impurity concentration; a high concentration region arranged closer to the front surface than the peak region and having an impurity concentration more gently sloped than the one or more peaks; and a low concentration region arranged closer to the front surface than the high concentration region and having an impurity concentration lower than the impurity concentration of the high concentration region and a substrate concentration of the semiconductor substrate.
    Type: Application
    Filed: August 29, 2017
    Publication date: January 4, 2018
    Inventors: Hiroshi TAKISHITA, Takashi YOSHIMURA, Takahiro TAMURA, Yuichi ONOZAWA, Akio YAMANO
  • Patent number: 9842918
    Abstract: A method of producing a semiconductor device is disclosed in which, after proton implantation is performed, a hydrogen-induced donor is formed by a furnace annealing process to form an n-type field stop layer. A disorder generated in a proton passage region is reduced by a laser annealing process to form an n-type disorder reduction region. As such, the n-type field stop layer and the n-type disorder reduction region are formed by the proton implantation. Therefore, it is possible to provide a stable and inexpensive semiconductor device which has low conduction resistance and can improve electrical characteristics, such as a leakage current, and a method for producing the semiconductor device.
    Type: Grant
    Filed: October 7, 2016
    Date of Patent: December 12, 2017
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Masayuki Miyazaki, Takashi Yoshimura, Hiroshi Takishita, Hidenao Kuribayashi
  • Publication number: 20170352768
    Abstract: Provided is a semiconductor device manufacturing method. The device has a substrate including one and another surfaces. A first semiconductor region of a first conductivity type is formed in the substrate. A second conductivity type, second semiconductor region is provided in a first surface layer, that includes the one surface, of the substrate. A first electrode is in contact with the second semiconductor region to form a junction therebetween. A first conductivity type, third semiconductor region is provided in a second surface layer, that includes the another surface, of the substrate. The third semiconductor region has a higher impurity concentration than the first semiconductor region. A fourth semiconductor region of the second conductivity type is provided in the first semiconductor region at a location deeper than the third semiconductor region from the another surface. A second electrode is in contact with the third semiconductor region.
    Type: Application
    Filed: August 24, 2017
    Publication date: December 7, 2017
    Applicant: FUJI ELECTRIC CO., LTD.
    Inventors: Yuichi ONOZAWA, Takashi YOSHIMURA, Hiroshi TAKISHITA
  • Publication number: 20170345888
    Abstract: Proton irradiation is performed a plurality of times from rear surface of an n-type semiconductor substrate, which is an n? drift layer, forming an n-type FS layer having lower resistance than the n-type semiconductor substrate in the rear surface of the n? drift layer. When the proton irradiation is performed a plurality of times, the next proton irradiation is performed to as to compensate for a reduction in mobility due to disorder which remains after the previous proton irradiation. In this case, the second or subsequent proton irradiation is performed at the position of the disorder which is formed by the previous proton irradiation. In this way, even after proton irradiation and a heat treatment, the disorder is reduced and it is possible to prevent deterioration of characteristics, such as increase in leakage current. It is possible to form an n-type FS layer including a high-concentration hydrogen-related donor layer.
    Type: Application
    Filed: July 28, 2017
    Publication date: November 30, 2017
    Inventors: Hiroshi TAKISHITA, Takashi YOSHIMURA, Masayuki MIYAZAKI, Hidenao KURIBAYASHI
  • Publication number: 20170317163
    Abstract: Hydrogen atoms and crystal defects are introduced into an n? semiconductor substrate by proton implantation. The crystal defects are generated in the n? semiconductor substrate by electron beam irradiation before or after the proton implantation. Then, a heat treatment for generating donors is performed. The amount of crystal defects is appropriately controlled during the heat treatment for generating donors to increase a donor generation rate. In addition, when the heat treatment for generating donors ends, the crystal defects formed by the electron beam irradiation and the proton implantation are recovered and controlled to an appropriate amount of crystal defects. Therefore, for example, it is possible to improve a breakdown voltage and reduce a leakage current.
    Type: Application
    Filed: July 17, 2017
    Publication date: November 2, 2017
    Inventors: Takashi YOSHIMURA, Masayuki MIYAZAKI, Hiroshi TAKISHITA, Hidenao KURIBAYASHI
  • Patent number: 9773923
    Abstract: Provided is a semiconductor device and a method for forming the same. The device has a substrate including one and another surfaces. A first semiconductor region of a first conductivity type is formed in the substrate. A second conductivity type, second semiconductor region is provided in a first surface layer, that includes the one surface, of the substrate. A first electrode is in contact with the second semiconductor region to form a junction therebetween. A first conductivity type, third semiconductor region is provided in a second surface layer, that includes the another surface, of the substrate. The third semiconductor region has a higher impurity concentration than the first semiconductor region. A fourth semiconductor region of the second conductivity type is provided in the first semiconductor region at a location deeper than the third semiconductor region from the another surface. A second electrode is in contact with the third semiconductor region.
    Type: Grant
    Filed: August 7, 2015
    Date of Patent: September 26, 2017
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Yuichi Onozawa, Takashi Yoshimura, Hiroshi Takishita
  • Publication number: 20170271447
    Abstract: Provided is a semiconductor device including a semiconductor substrate doped with impurities, a front surface-side electrode provided on a front surface side of the semiconductor substrate, a back surface-side electrode provided on a back surface side of the semiconductor substrate, wherein the semiconductor substrate has a peak region arranged on the back surface side of the semiconductor substrate and having one or more peaks of impurity concentration, a high concentration region arranged closer to the front surface than the peak region and having a gentler impurity concentration than the one or more peaks, and a low concentration region arranged closer to the front surface than the high concentration region and having a lower impurity concentration than the high concentration region.
    Type: Application
    Filed: May 30, 2017
    Publication date: September 21, 2017
    Inventors: Takahiro TAMURA, Yuichi ONOZAWA, Takashi YOSHIMURA, Hiroshi TAKISHITA, Akio YAMANO
  • Patent number: 9768246
    Abstract: Hydrogen atoms and crystal defects are introduced into an n? semiconductor substrate by proton implantation. The crystal defects are generated in the n? semiconductor substrate by electron beam irradiation before or after the proton implantation. Then, a heat treatment for generating donors is performed. The amount of crystal defects is appropriately controlled during the heat treatment for generating donors to increase a donor generation rate. In addition, when the heat treatment for generating donors ends, the crystal defects formed by the electron beam irradiation and the proton implantation are recovered and controlled to an appropriate amount of crystal defects. Therefore, for example, it is possible to improve a breakdown voltage and reduce a leakage current.
    Type: Grant
    Filed: January 28, 2016
    Date of Patent: September 19, 2017
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Takashi Yoshimura, Masayuki Miyazaki, Hiroshi Takishita, Hidenao Kuribayashi
  • Patent number: 9722016
    Abstract: Proton irradiation is performed a plurality of times from rear surface of an n-type semiconductor substrate, which is an n? drift layer, forming an n-type FS layer having lower resistance than the n-type semiconductor substrate in the rear surface of the n? drift layer. When the proton irradiation is performed a plurality of times, the next proton irradiation is performed to as to compensate for a reduction in mobility due to disorder which remains after the previous proton irradiation. In this case, the second or subsequent proton irradiation is performed at the position of the disorder which is formed by the previous proton irradiation. In this way, even after proton irradiation and a heat treatment, the disorder is reduced and it is possible to prevent deterioration of characteristics, such as increase in leakage current. It is possible to form an n-type FS layer including a high-concentration hydrogen-related donor layer.
    Type: Grant
    Filed: May 17, 2016
    Date of Patent: August 1, 2017
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Hiroshi Takishita, Takashi Yoshimura, Masayuki Miyazaki, Hidenao Kuribayashi
  • Publication number: 20170025520
    Abstract: A method of producing a semiconductor device is disclosed in which, after proton implantation is performed, a hydrogen-induced donor is formed by a furnace annealing process to form an n-type field stop layer. A disorder generated in a proton passage region is reduced by a laser annealing process to form an n-type disorder reduction region. As such, the n-type field stop layer and the n-type disorder reduction region are formed by the proton implantation. Therefore, it is possible to provide a stable and inexpensive semiconductor device which has low conduction resistance and can improve electrical characteristics, such as a leakage current, and a method for producing the semiconductor device.
    Type: Application
    Filed: October 7, 2016
    Publication date: January 26, 2017
    Inventors: Masayuki MIYAZAKI, Takashi YOSHIMURA, Hiroshi TAKISHITA, Hidenao KURIBAYASHI