Patents by Inventor Michio Nemoto
Michio Nemoto 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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Patent number: 11935945Abstract: Provided is a semiconductor device, comprising: a semiconductor substrate having an upper surface, a lower surface, and a center position equidistant from the upper surface and the lower surface in a depth direction of the semiconductor substrate. An N-type region with an N-type conductivity is provided in the semiconductor substrate such that the N-type region includes the center position of the semiconductor substrate. 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 of the semiconductor substrate.Type: GrantFiled: April 21, 2021Date of Patent: March 19, 2024Assignee: FUJI ELECTRIC CO., LTD.Inventors: Hiroshi Takishita, Takashi Yoshimura, Misaki Meguro, Michio Nemoto
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Patent number: 11894258Abstract: There is provided a semiconductor device including: an anode electrode that is provided on a front surface side of a semiconductor substrate; a drift region of a first conductivity type that is provided in the semiconductor substrate; a first anode region of a first conductivity type that is in Schottky contact with the anode electrode; and a second anode region of a second conductivity type that is different from the first conductivity type, in which the first anode region has a doping concentration lower than or equal to a doping concentration of the second anode region, and is spaced from the drift region by the second anode region.Type: GrantFiled: May 31, 2022Date of Patent: February 6, 2024Assignee: FUJI ELECTRIC CO., LTD.Inventors: Takahiro Tamura, Michio Nemoto
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Publication number: 20220293775Abstract: There is provided a semiconductor device including: an anode electrode that is provided on a front surface side of a semiconductor substrate; a drift region of a first conductivity type that is provided in the semiconductor substrate; a first anode region of a first conductivity type that is in Schottky contact with the anode electrode; and a second anode region of a second conductivity type that is different from the first conductivity type, in which the first anode region has a doping concentration lower than or equal to a doping concentration of the second anode region, and is spaced from the drift region by the second anode region.Type: ApplicationFiled: May 31, 2022Publication date: September 15, 2022Inventors: Takahiro TAMURA, Michio NEMOTO
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Publication number: 20220216056Abstract: Provided is a semiconductor device including: a semiconductor substrate having an upper surface and a lower surface, and containing a bulk donor; a buffer region of a first conductivity type; a high-concentration region of a first conductivity type; and a lower surface region of a first conductivity type or a second conductivity type, wherein a shallowest doping concentration peak closest to the lower surface of the semiconductor substrate among the doping concentration peaks of the buffer region is a concentration peak of a hydrogen donor having a concentration higher than the other doping concentration peaks, and a ratio A/B of a peak concentration A of the shallowest doping concentration peak and an average peak concentration B of the other doping concentration peaks is 200 or less.Type: ApplicationFiled: March 24, 2022Publication date: July 7, 2022Inventors: Misaki UCHIDA, Takashi YOSHIMURA, Hiroshi TAKISHITA, Motoyoshi KUBOUCHI, Michio NEMOTO
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Publication number: 20220216055Abstract: Provided is a semiconductor device including: a semiconductor substrate having an upper surface and a lower surface, and containing a bulk donor; a buffer region of a first conductivity type which is disposed on the lower surface side of the semiconductor substrate and contains a hydrogen donor, and in which a doping concentration distribution in a depth direction of the semiconductor substrate has a single first doping concentration peak; a high-concentration region of a first conductivity type which is disposed between the buffer region and the upper surface of the semiconductor substrate, contains a hydrogen donor, and has a donor concentration higher than a bulk donor concentration; and a lower surface region of a first conductivity type or a second conductivity type which is disposed between the buffer region and a lower surface of the semiconductor substrate, and has a doping concentration higher than the high-concentration region.Type: ApplicationFiled: March 24, 2022Publication date: July 7, 2022Inventors: Motoyoshi KUBOUCHI, Takashi YOSHIMURA, Hiroshi TAKISHITA, Misaki UCHIDA, Michio NEMOTO
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Patent number: 11362202Abstract: There is provided a semiconductor device including: an anode electrode that is provided on a front surface side of a semiconductor substrate; a drift region of a first conductivity type that is provided in the semiconductor substrate; a first anode region of a first conductivity type that is in Schottky contact with the anode electrode; and a second anode region of a second conductivity type that is different from the first conductivity type, in which the first anode region has a doping concentration lower than or equal to a doping concentration of the second anode region, and is spaced from the drift region by the second anode region.Type: GrantFiled: August 13, 2020Date of Patent: June 14, 2022Assignee: FUJI ELECTRIC CO., LTD.Inventors: Takahiro Tamura, Michio Nemoto
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Publication number: 20220084828Abstract: 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: ApplicationFiled: November 24, 2021Publication date: March 17, 2022Inventors: Kosuke YOSHIDA, Takashi YOSHIMURA, Hiroshi TAKISHITA, Misaki UCHIDA, Michio NEMOTO, Nao SUGANUMA, Motoyoshi KUBOUCHI
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Publication number: 20220013368Abstract: 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: ApplicationFiled: September 28, 2021Publication date: January 13, 2022Inventors: Yasunori AGATA, Takashi YOSHIMURA, Hiroshi TAKISHITA, Misaki UCHIDA, Michio NEMOTO, Toru AJIKI, Yuichi ONOZAWA
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Patent number: 11195941Abstract: Provided is a semiconductor device including a semiconductor substrate having a drift region; a transistor portion having a collector region; a diode portion having a cathode region; and a boundary portion arranged between the transistor portion and the diode portion at an upper surface of the semiconductor substrate, and having the collector region, wherein the mesa portion of each of the transistor portion and the boundary portion has an emitter region and a base region, the base region has a channel portion, and a density in the upper surface of the mesa portion in the region in which the channel portion is projected onto the upper surface of the mesa portion of the boundary portion may be smaller than the density of the region in which the channel portion is projected onto the upper surface of the mesa portion of the transistor portion.Type: GrantFiled: September 30, 2019Date of Patent: December 7, 2021Assignee: FUJI ELECTRIC CO., LTD.Inventors: Takahiro Tamura, Michio Nemoto
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Publication number: 20210265492Abstract: 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: ApplicationFiled: April 21, 2021Publication date: August 26, 2021Inventors: Hiroshi TAKISHITA, Takashi YOSHIMURA, Misaki MEGURO, Michio NEMOTO
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Patent number: 10998398Abstract: A semiconductor device includes a plurality of broad buffer layers provided in a drift layer. Each of the plurality of the broad buffer layers has an impurity concentration exceeding that of a portion of the drift layer excluding the broad buffer layers, and has a mountain-shaped impurity concentration distribution in which a local maximum value is less than the impurity concentration of an anode layer and a cathode layer. The plurality of broad buffer layers are disposed at different depths from a first main surface of the drift layer, respectively, the number of broad buffer layers close to the first main surface from the intermediate position of the drift layer is at least one, and number of broad buffer layers close to a second main surface of the drift layer from the intermediate position of the drift layer is at least two. The broad buffer layer includes a hydrogen-related donor.Type: GrantFiled: November 19, 2020Date of Patent: May 4, 2021Assignee: FUJI ELECTRIC CO., LTD.Inventors: Michio Nemoto, Takashi Yoshimura
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Publication number: 20210091175Abstract: A semiconductor device includes a plurality of broad buffer layers provided in a drift layer. Each of the plurality of the broad buffer layers has an impurity concentration exceeding that of a portion of the drift layer excluding the broad buffer layers, and has a mountain-shaped impurity concentration distribution in which a local maximum value is less than the impurity concentration of an anode layer and a cathode layer. The plurality of broad buffer layers are disposed at different depths from a first main surface of the drift layer, respectively, the number of broad buffer layers close to the first main surface from the intermediate position of the drift layer is at least one, and number of broad buffer layers close to a second main surface of the drift layer from the intermediate position of the drift layer is at least two. The broad buffer layer includes a hydrogen-related donor.Type: ApplicationFiled: November 19, 2020Publication date: March 25, 2021Inventors: Michio NEMOTO, Takashi YOSHIMURA
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Publication number: 20210050345Abstract: There is provided a semiconductor device including: an anode electrode that is provided on a front surface side of a semiconductor substrate; a drift region of a first conductivity type that is provided in the semiconductor substrate; a first anode region of a first conductivity type that is in Schottky contact with the anode electrode; and a second anode region of a second conductivity type that is different from the first conductivity type, in which the first anode region has a doping concentration lower than or equal to a doping concentration of the second anode region, and is spaced from the drift region by the second anode region.Type: ApplicationFiled: August 13, 2020Publication date: February 18, 2021Inventors: Takahiro TAMURA, Michio NEMOTO
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Patent number: 10868111Abstract: A semiconductor device includes a plurality of broad buffer layers provided in a drift layer. Each of the plurality of the broad buffer layers has an impurity concentration exceeding that of a portion of the drift layer excluding the broad buffer layers, and has a mountain-shaped impurity concentration distribution in which a local maximum value is less than the impurity concentration of an anode layer and a cathode layer. The plurality of broad buffer layers are disposed at different depths from a first main surface of the drift layer, respectively, the number of broad buffer layers close to the first main surface from the intermediate position of the drift layer is at least one, and number of broad buffer layers close to a second main surface of the drift layer from the intermediate position of the drift layer is at least two. The broad buffer layer includes a hydrogen-related donor.Type: GrantFiled: July 27, 2018Date of Patent: December 15, 2020Assignee: FUJI ELECTRIC CO., LTD.Inventors: Michio Nemoto, Takashi Yoshimura
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Patent number: 10847608Abstract: A p anode layer is formed on one main surface of an n? drift layer. N+ cathode layer having an impurity concentration more than that of the n? drift layer is formed on the other main surface. An anode electrode is formed on the surface of the p anode layer. A cathode electrode is formed on the surface of the n+ cathode layer. N-type broad buffer region having a net doping concentration more than the bulk impurity concentration of a wafer and less than the n+ cathode layer and p anode layer is formed in the n? drift layer. Resistivity ?0 of the n? drift layer satisfies 0.12V0??0?0.25V0 with respect to rated voltage V0. Total amount of net doping concentration of the broad buffer region is equal to or more than 4.8×1011 atoms/cm2 and equal to or less than 1.0×1012 atoms/cm2.Type: GrantFiled: March 20, 2020Date of Patent: November 24, 2020Assignee: FUJI ELECTRIC CO., LTD.Inventors: Michio Nemoto, Takashi Yoshimura
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Publication number: 20200219971Abstract: A p anode layer is formed on one main surface of an n? drift layer. N+ cathode layer having an impurity concentration more than that of the n? drift layer is formed on the other main surface. An anode electrode is formed on the surface of the p anode layer. A cathode electrode is formed on the surface of the n+ cathode layer. N-type broad buffer region having a net doping concentration more than the bulk impurity concentration of a wafer and less than the n+ cathode layer and p anode layer is formed in the n? drift layer. Resistivity ?0 of the n? drift layer satisfies 0.12V0??0?0.25V0 with respect to rated voltage V0. Total amount of net doping concentration of the broad buffer region is equal to or more than 4.8×1011 atoms/cm2 and equal to or less than 1.0×1012 atoms/cm2.Type: ApplicationFiled: March 20, 2020Publication date: July 9, 2020Inventors: Michio NEMOTO, Takashi YOSHIMURA
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Patent number: 10636868Abstract: A semiconductor device includes a plurality of broad buffer layers provided in a drift layer. Each of the plurality of the broad buffer layers has an impurity concentration exceeding that of a portion of the drift layer excluding the broad buffer layers, and has a mountain-shaped impurity concentration distribution in which a local maximum value is less than the impurity concentration of an anode layer and a cathode layer. The plurality of broad buffer layers are disposed at different depths from a first main surface of the drift layer, respectively, the number of broad buffer layers close to the first main surface from the intermediate position of the drift layer is at least one, and number of broad buffer layers close to a second main surface of the drift layer from the intermediate position of the drift layer is at least two. The broad buffer layer includes a hydrogen-related donor.Type: GrantFiled: July 27, 2018Date of Patent: April 28, 2020Assignee: FUJI ELECTRIC CO., LTD.Inventors: Michio Nemoto, Takashi Yoshimura
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Publication number: 20200035817Abstract: Provided is a semiconductor device including a semiconductor substrate having a drift region; a transistor portion having a collector region; a diode portion having a cathode region; and a boundary portion arranged between the transistor portion and the diode portion at an upper surface of the semiconductor substrate, and having the collector region, wherein the mesa portion of each of the transistor portion and the boundary portion has an emitter region and a base region, the base region has a channel portion, and a density in the upper surface of the mesa portion in the region in which the channel portion is projected onto the upper surface of the mesa portion of the boundary portion may be smaller than the density of the region in which the channel portion is projected onto the upper surface of the mesa portion of the transistor portion.Type: ApplicationFiled: September 30, 2019Publication date: January 30, 2020Inventors: Takahiro TAMURA, Michio NEMOTO
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Publication number: 20180350902Abstract: A p anode layer is formed on one main surface of an n? drift layer. N+ cathode layer having an impurity concentration more than that of the n? drift layer is formed on the other main surface. An anode electrode is formed on the surface of the p anode layer. A cathode electrode is formed on the surface of the n+ cathode layer. N-type broad buffer region having a net doping concentration more than the bulk impurity concentration of a wafer and less than the n+ cathode layer and p anode layer is formed in the n? drift layer. Resistivity ?0 of the n? drift layer satisfies 0.12V0??0?0.25V0 with respect to rated voltage V0. Total amount of net doping concentration of the broad buffer region is equal to or more than 4.8×1011 atoms/cm2 and equal to or less than 1.0×1012 atoms/cm2.Type: ApplicationFiled: July 27, 2018Publication date: December 6, 2018Inventors: Michio NEMOTO, Takashi YOSHIMURA
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Patent number: 10068998Abstract: A semiconductor device is provided in which a semiconductor substrate can be prevented from being broken while elements can be prevented from being destroyed by a snap-back phenomenon. After an MOS gate structure is formed in a front surface of an FZ wafer, a rear surface of the FZ wafer is ground. Then, the ground surface is irradiated with protons and irradiated with two kinds of laser beams different in wavelength simultaneously to thereby form an N+ first buffer layer and an N second buffer layer. Then, a P+ collector layer and a collector electrode are formed on the proton-irradiated surface. The distance from a position where the net doping concentration of the N+ first buffer layer is locally maximized to the interface between the P+ collector layer and the N second buffer layer is set to be in a range of 5 ?m to 30 ?m, both inclusively.Type: GrantFiled: November 18, 2011Date of Patent: September 4, 2018Assignee: FUJI ELECTRIC CO., LTD.Inventors: Michio Nemoto, Haruo Nakazawa