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: 11335772
    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: Grant
    Filed: August 19, 2020
    Date of Patent: May 17, 2022
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Takahiro Tamura, Yuichi Onozawa, Takashi Yoshimura, Hiroshi Takishita, Akio Yamano
  • Publication number: 20220140091
    Abstract: Provided is a semiconductor device including a semiconductor substrate; a hydrogen donor that is provide inside the semiconductor substrate in a depth direction, has a doping concentration that is higher than a doping concentration of a dopant of the semiconductor substrate, has a doping concentration distribution peak at a first position that is a predetermined distance in the depth direction of the semiconductor substrate away from one main surface of the semiconductor substrate, and has a tail of the doping concentration distribution where the doping concentration is lower than at the peak, farther on the one main surface side than where the first position is located; and a crystalline defect region having a crystalline defect density center peak at a position shallower than the first position, in the depth direction of the semiconductor substrate.
    Type: Application
    Filed: January 17, 2022
    Publication date: May 5, 2022
    Inventors: Takashi YOSHIMURA, Yuichi ONOZAWA, Hiroshi TAKISHITA, Misaki MEGURO, Motoyoshi KUBOUCHI, Naoko KODAMA
  • Publication number: 20220084828
    Abstract: Provided is a semiconductor apparatus including: a first peak of a hydrogen chemical concentration disposed on the lower surface side of the semiconductor substrate; and a flat portion disposed on the upper surface side of the semiconductor substrate with respect to the first peak, containing a hydrogen donor, and having a substantially (almost) flat donor concentration distribution in a depth direction. An oxygen contribution ratio indicating a ratio of an oxygen chemical concentration contributing to generation of the hydrogen donor in the oxygen chemical concentration of the oxygen ranges from 1×10?5 to 7×10?4. A concentration of the oxygen contributing to generation of the hydrogen donor in the flat portion is lower than the hydrogen chemical concentration. A hydrogen donor concentration in the flat portion ranges from 2×1012/cm3 to 5×1014/cm3.
    Type: Application
    Filed: November 24, 2021
    Publication date: March 17, 2022
    Inventors: Kosuke YOSHIDA, Takashi YOSHIMURA, Hiroshi TAKISHITA, Misaki UCHIDA, Michio NEMOTO, Nao SUGANUMA, Motoyoshi KUBOUCHI
  • Patent number: 11239324
    Abstract: Provided is a semiconductor device including a semiconductor substrate; a hydrogen donor that is provide inside the semiconductor substrate in a depth direction, has a doping concentration that is higher than a doping concentration of a dopant of the semiconductor substrate, has a doping concentration distribution peak at a first position that is a predetermined distance in the depth direction of the semiconductor substrate away from one main surface of the semiconductor substrate, and has a tail of the doping concentration distribution where the doping concentration is lower than at the peak, farther on the one main surface side than where the first position is located; and a crystalline defect region having a crystalline defect density center peak at a position shallower than the first position, in the depth direction of the semiconductor substrate.
    Type: Grant
    Filed: February 24, 2020
    Date of Patent: February 1, 2022
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Takashi Yoshimura, Yuichi Onozawa, Hiroshi Takishita, Misaki Meguro, Motoyoshi Kubouchi, Naoko Kodama
  • Publication number: 20220013368
    Abstract: Provided is a semiconductor device, including a semiconductor substrate having an upper surface and a lower surface and including a bulk donor, wherein a hydrogen chemical concentration distribution of the semiconductor substrate in a depth direction is flat, monotonically increasing, or monotonically decreasing from the lower surface to the upper surface except for a portion where a local hydrogen concentration peak is provided; and a donor concentration of the semiconductor substrate is higher than a bulk donor concentration over an entire region from the upper surface to the lower surface. Hydrogen ions may be irradiated from the upper surface or the lower surface of the semiconductor substrate so as to penetrate the semiconductor substrate in the depth direction.
    Type: Application
    Filed: September 28, 2021
    Publication date: January 13, 2022
    Inventors: Yasunori AGATA, Takashi YOSHIMURA, Hiroshi TAKISHITA, Misaki UCHIDA, Michio NEMOTO, Toru AJIKI, Yuichi ONOZAWA
  • Publication number: 20210265492
    Abstract: Provided is a semiconductor device, comprising: a semiconductor substrate provided with an N-type region, wherein the N-type region is a region including a center position in a depth direction of the semiconductor substrate; and the N-type region includes an acceptor with a concentration that is a lower concentration than a carrier concentration, and is 0.001 times or more of a carrier concentration at the center position. A semiconductor device can be manufactured by a manufacturing method, comprising: a preparation step configured to prepare a P-type semiconductor substrate; and a first inverting step configured to form an N-type region including a center position in a depth direction of the semiconductor substrate, by implanting an N-type impurity into the P-type semiconductor substrate and performing heat treatment.
    Type: Application
    Filed: April 21, 2021
    Publication date: August 26, 2021
    Inventors: Hiroshi TAKISHITA, Takashi YOSHIMURA, Misaki MEGURO, Michio NEMOTO
  • Patent number: 11081410
    Abstract: A method of manufacturing a semiconductor device from a semiconductor wafer in which a plurality of semiconductor chips are formed. The method includes a first process of forming an active region on a first main surface side of the semiconductor wafer and a second process of forming a first process control monitor (PCM) on a second main surface side of the semiconductor wafer. The method further includes before the second process, a third process of forming a second PCM on the first main surface side of the semiconductor wafer. The first PCM and the second PCM are formed at an area located at the same position in a plan view of the semiconductor wafer.
    Type: Grant
    Filed: August 27, 2019
    Date of Patent: August 3, 2021
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Hiroshi Takishita, Kazuhiro Kitahara, Ryouichi Kawano, Motoyoshi Kubouchi
  • Publication number: 20210159317
    Abstract: A p-type semiconductor region is formed in a front surface side of an n-type semiconductor substrate. An n-type field stop (FS) region including protons as a donor is formed in a rear surface side of the semiconductor substrate. A concentration distribution of the donors in the FS region include first, second, third and fourth peaks in order from a front surface to the rear surface. Each of the peaks has a peak maximum point, and peak end points formed at both sides of the peak maximum point. The peak maximum points of the first and second peaks are higher than the peak maximum point of the third peak. The peak maximum point of the third peak is lower than the peak maximum point of the fourth peak.
    Type: Application
    Filed: February 4, 2021
    Publication date: May 27, 2021
    Inventors: Hiroki WAKIMOTO, Hiroshi TAKISHITA, Takashi YOSHIMURA, Takahiro TAMURA, Yuichi ONOZAWA
  • Publication number: 20210143252
    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: January 19, 2021
    Publication date: May 13, 2021
    Inventors: Takashi YOSHIMURA, Masayuki MIYAZAKI, Hiroshi TAKISHITA, Hidenao KURIBAYASHI
  • Publication number: 20210111026
    Abstract: A laser annealing method for a semiconductor device, includes: a first step of adding an impurity to a semiconductor substrate; and a second step of irradiating a region to which the impurity is added with a pulsed laser beam a plurality of times to anneal the semiconductor substrate. In the second step, a first region of a portion of the region to which the impurity is added is irradiated with the pulsed laser beam, and after a predetermined time interval, a second region adjacent to the first region is irradiated with the pulsed laser beam. The predetermined time interval is larger than a pulse interval of the pulsed laser beam.
    Type: Application
    Filed: December 21, 2020
    Publication date: April 15, 2021
    Inventors: Takeshi Aiba, Hiroshi Takishita, Takashi Yoshimura
  • Publication number: 20210104407
    Abstract: There is provided a semiconductor device, a hydrogen concentration distribution has a hydrogen concentration peak, a helium concentration distribution has a helium concentration peak, and a donor concentration distribution has a first donor concentration peak and a second donor concentration peak; the hydrogen concentration peak and the first donor concentration peak are located at a first depth, and the helium concentration peak and the second donor concentration peak are located at a second depth; each concentration peak has an upward slope; and a value which is obtained by normalizing a gradient of the upward slope of the second donor concentration peak by a gradient of the upward slope of the helium concentration peak is smaller than a value which is obtained by normalizing a gradient of the upward slope of the first donor concentration peak by a gradient of the upward slope of the hydrogen concentration peak.
    Type: Application
    Filed: November 30, 2020
    Publication date: April 8, 2021
    Inventors: Misaki MEGURO, Takashi YOSHIMURA, Hiroshi TAKISHITA, Naoko KODAMA, Yasunori AGATA
  • Publication number: 20210082702
    Abstract: A semiconductor device wherein a hydrogen concentration distribution has a first hydrogen concentration peak and a second hydrogen concentration peak and a donor concentration distribution has a first donor concentration peak and a second donor concentration peak in a depth direction, wherein the first hydrogen concentration peak and the first donor concentration peak are placed at a first depth and the second hydrogen concentration peak and the second donor concentration peak are placed at a second depth deeper than the first depth relative to the lower surface is provided.
    Type: Application
    Filed: September 28, 2020
    Publication date: March 18, 2021
    Inventors: Yasunori AGATA, Takashi YOSHIMURA, Hiroshi TAKISHITA, Misaki MEGURO, Naoko KODAMA, Yoshihiro IKURA, Seiji NOGUCHI, Yuichi HARADA, Yosuke SAKURAI
  • Patent number: 10950446
    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: Grant
    Filed: October 23, 2019
    Date of Patent: March 16, 2021
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Hiroshi Takishita, Takashi Yoshimura, Takahiro Tamura, Yuichi Onozawa, Akio Yamano
  • Patent number: 10930733
    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: June 3, 2019
    Date of Patent: February 23, 2021
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Takashi Yoshimura, Masayuki Miyazaki, Hiroshi Takishita, Hidenao Kuribayashi
  • Patent number: 10923570
    Abstract: A semiconductor device comprises: an n-type semiconductor substrate; a p-type anode region formed in the semiconductor substrate on its front surface side; an n-type field stop region formed in the semiconductor substrate on its rear surface side with protons as a donor; and an n-type cathode region formed in the semiconductor substrate to be closer to its rear surface than the field stop region is, wherein a concentration distribution of the donor in the field stop region in its depth direction has a first peak, and a second peak that is closer to the rear surface of the semiconductor substrate than the first peak is, and has a concentration lower than that of the first peak, and a carrier lifetime in at least a partial region between the anode region and the cathode region is longer than carrier lifetimes in the anode region.
    Type: Grant
    Filed: June 4, 2019
    Date of Patent: February 16, 2021
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Hiroki Wakimoto, Hiroshi Takishita, Takashi Yoshimura, Takahiro Tamura, Yuichi Onozawa
  • Publication number: 20210043738
    Abstract: Provided is a semiconductor device including a buffer region. Provided is a semiconductor device including: semiconductor substrate of a first conductivity type; a drift layer of the first conductivity type provided in the semiconductor substrate; and a buffer region of the first conductivity type provided in the drift layer, the buffer region having a plurality of peaks of a doping concentration, wherein the buffer region has: a first peak which has a predetermined doping concentration, and is provided the closest to a back surface of the semiconductor substrate among the plurality of peaks; and a high-concentration peak which has a higher doping concentration than the first peak, and is provided closer to an upper surface of the semiconductor substrate than the first peak is.
    Type: Application
    Filed: October 22, 2020
    Publication date: February 11, 2021
    Inventors: Yasunori AGATA, Takashi YOSHIMURA, Hiroshi TAKISHITA
  • Publication number: 20210043739
    Abstract: Provided is a semiconductor device comprising a semiconductor substrate, wherein the semiconductor substrate includes a hydrogen containing region including hydrogen, and the hydrogen containing region includes a high concentration region with a higher carrier concentration than a virtual carrier concentration determined based on a concentration of hydrogen included and an activation ratio of hydrogen. The semiconductor substrate includes an N type drift region, an N type emitter region that has a higher carrier concentration than that in the drift region, a P type base region, a P type collector region provided to be in contact with a lower surface of the semiconductor substrate, and an N type buffer region that is provided between the collector region and the drift region, and has a higher carrier concentration than that in the drift region, and the hydrogen containing region is included in the buffer region.
    Type: Application
    Filed: October 22, 2020
    Publication date: February 11, 2021
    Inventors: Yoshiharu KATO, Toru AJIKI, Tohru SHIRAKAWA, Misaki TAKAHASHI, Kaname MITSUZUKA, Takashi YOSHIMURA, Yuichi ONOZAWA, Hiroshi TAKISHITA, Soichi YOSHIDA
  • Publication number: 20200381515
    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: August 19, 2020
    Publication date: December 3, 2020
    Inventors: Takahiro TAMURA, Yuichi ONOZAWA, Takashi YOSHIMURA, Hiroshi TAKISHITA, Akio YAMANO
  • Patent number: 10847609
    Abstract: A front surface element structure is formed on the front surface side of an n?-type semiconductor substrate. Then defects are formed throughout an n?-type semiconductor substrate to adjust a carrier lifetime. Hydrogen ions are ion-implanted from a rear surface side of the n?-type semiconductor substrate, and a hydrogen implanted region having a hydrogen concentration higher than a hydrogen concentration of a bulk substrate is formed in the surface layer of a rear surface side of the n?-type semiconductor substrate.
    Type: Grant
    Filed: January 8, 2020
    Date of Patent: November 24, 2020
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Yuichi Onozawa, Hiroshi Takishita, Takashi Yoshimura
  • Patent number: 10825904
    Abstract: Provided is a semiconductor device including a buffer region. Provided is a semiconductor device including: semiconductor substrate of a first conductivity type; a drift layer of the first conductivity type provided in the semiconductor substrate; and a buffer region of the first conductivity type provided in the drift layer, the buffer region having a plurality of peaks of a doping concentration, wherein the buffer region has: a first peak which has a predetermined doping concentration, and is provided the closest to a back surface of the semiconductor substrate among the plurality of peaks; and a high-concentration peak which has a higher doping concentration than the first peak, and is provided closer to an upper surface of the semiconductor substrate than the first peak is.
    Type: Grant
    Filed: December 21, 2018
    Date of Patent: November 3, 2020
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Yasunori Agata, Takashi Yoshimura, Hiroshi Takishita