Patents by Inventor Akihiko Furukawa
Akihiko Furukawa 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: 11901444Abstract: Examples of a semiconductor device includes a transistor region formed in a semiconductor substrate having a first conductivity type drift layer, and a diode region formed to be adjacent to the transistor region in the semiconductor substrate, wherein the diode region has a second conductivity type anode layer formed on the drift layer and a first conductivity type cathode layer formed on the lower side of the drift layer, and the cathode layer has an adjacent region contacting the transistor region, the adjacent region having a depth, from a lower surface of the semiconductor substrate, which becomes shallower toward the transistor region and having first conductivity type impurity concentration which decreases toward the transistor region.Type: GrantFiled: May 3, 2022Date of Patent: February 13, 2024Assignee: Mitsubishi Electric CorporationInventors: Ryu Kamibaba, Tetsuo Takahashi, Akihiko Furukawa
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Patent number: 11869962Abstract: Examples of a semiconductor device includes a transistor region formed in a semiconductor substrate having a first conductivity type drift layer, and a diode region formed to be adjacent to the transistor region in the semiconductor substrate, wherein the diode region has a second conductivity type anode layer formed on the drift layer and a first conductivity type cathode layer formed on the lower side of the drift layer, and the cathode layer has an adjacent region contacting the transistor region, the adjacent region having a depth, from a lower surface of the semiconductor substrate, which becomes shallower toward the transistor region and having first conductivity type impurity concentration which decreases toward the transistor region.Type: GrantFiled: May 3, 2022Date of Patent: January 9, 2024Assignee: Mitsubishi Electric CorporationInventors: Ryu Kamibaba, Tetsuo Takahashi, Akihiko Furukawa
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Publication number: 20230253345Abstract: A semiconductor device includes a field insulating film formed on an epitaxial layer, a front surface electrode covering an inner peripheral end of the field insulating film, and an outer peripheral electrode covering an outer peripheral end of the field insulating film. In a surface layer portion of the epitaxial layer, a termination well region that is connected to the front surface electrode and extends to the outside of an outer peripheral end of the front surface electrode is formed. The semi-insulating film is formed so as to cover a part of the field insulating film apart from the front surface electrode and the outer peripheral electrode. The semi-insulating film is connected to the epitaxial layer through an opening formed in the field insulating film in each of a region inside and a region outside an outer peripheral end of the termination well region.Type: ApplicationFiled: November 21, 2022Publication date: August 10, 2023Applicant: Mitsubishi Electric CorporationInventors: Kohei EBIHARA, Fumihito MASUOKA, Masanori TSUKUDA, Akihiko FURUKAWA
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Patent number: 11699744Abstract: A semiconductor device includes; a semiconductor substrate; an emitter electrode provided on the semiconductor substrate; a gate electrode provided on the semiconductor substrate; a drift layer of a first conduction type provided in the semiconductor substrate; a source layer of the first conduction type provided on an upper surface side of the semiconductor substrate; a base layer of a second conduction type provided on the upper surface side of the semiconductor substrate; a collector electrode provided below the semiconductor substrate; and a two-part dummy active trench including, at an upper part, an upper dummy part not connected with the gate electrode and including, at a lower part, a lower active part connected with the gate electrode and covered by an insulating film, in a trench of the semiconductor substrate, wherein a longitudinal length of the lower active part is larger than a width of the lower active part.Type: GrantFiled: June 28, 2021Date of Patent: July 11, 2023Assignee: Mitsubishi Electric CorporationInventors: Kazuya Konishi, Koichi Nishi, Akihiko Furukawa
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Publication number: 20230083162Abstract: A diode region includes: an n-type first semiconductor layer provided on a second-main-surface side in the semiconductor substrate; an n-type second semiconductor layer provided on the first semiconductor layer; a p-type third semiconductor layer provided closer to a first main surface of the semiconductor substrate than the second semiconductor layer; a first main electrode that applies a first potential to the diode; a second main electrode that applies a second potential to the diode; and a dummy active trench gate provided so as to extend from the first main surface of the semiconductor substrate and reach the second semiconductor layer. The dummy active trench gate includes the third semiconductor layer that is not applied with the first potential to be in a floating state on at least one of two side surfaces, and the dummy active trench gate is applied with a gate potential of the transistor.Type: ApplicationFiled: June 24, 2022Publication date: March 16, 2023Applicant: Mitsubishi Electric CorporationInventors: Kazuya KONISHI, Akihiko FURUKAWA, Koichi NISHI, Hidenori FUJII, Shinya SONEDA, Yasuo KONISHI
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Publication number: 20230073864Abstract: When a positive gate voltage is applied to a first one of a first gate electrode and a second gate electrode, and current flows from a collector electrode to an emitter electrode, a semiconductor device applies a positive gate voltage to a second one of the first gate electrode and the second gate electrode. When a positive gate voltage is applied to the first one and current flows from the emitter electrode to the collector electrode, the semiconductor device applies voltage equal to or less than reference voltage to the second one.Type: ApplicationFiled: June 21, 2022Publication date: March 9, 2023Applicant: Mitsubishi Electric CorporationInventors: Koichi NISHI, Masanori TSUKUDA, Shinya SONEDA, Akihiko FURUKAWA
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Publication number: 20230027990Abstract: All of four of built-in gate resistance trenches function as practical built-in gate resistance trenches. A first end portion of each of four of the built-in gate resistance trenches is electrically connected to a wiring side contact region of a gate wiring via a wiring contact. A second end portion of each of four of the built-in gate resistance trenches is electrically connected to a pad side contact region of a gate pad via a pad contact. In each of four of the built-in gate resistance trenches, a distance between the wiring contact and the pad contact is defined as an inter-contact distance.Type: ApplicationFiled: April 22, 2022Publication date: January 26, 2023Applicant: Mitsubishi Electric CorporationInventors: Koichi NISHI, Shinya SONEDA, Akihiko FURUKAWA
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Publication number: 20230005809Abstract: In a semiconductor device according to the technology disclosed in the present specification, a temperature detection region is provided with a diffusion layer of a second conductivity type provided on a surface layer of a drift layer of a first conductivity type, a well layer of a first conductivity type provided on a surface layer of the diffusion layer and electrically connected to an anode electrode, and a cathode layer of a first conductivity type provided on a surface layer of the well layer and electrically connected to a cathode electrode.Type: ApplicationFiled: April 13, 2022Publication date: January 5, 2023Applicant: Mitsubishi Electric CorporationInventors: Shinya SONEDA, Akihiko FURUKAWA
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Publication number: 20220416064Abstract: A semiconductor device includes a capacitance adjusting region. The capacitance adjusting region includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a plurality of control trench gates. The first semiconductor layer is provided as a surface layer at an upper surface of the semiconductor substrate. The second semiconductor layer is selectively provided at an upper surface of the first semiconductor layer. The second semiconductor layer contacts a side surface of each of the control trench gates. The first semiconductor layer and the second semiconductor layer are electrically connected to an emitter electrode of a transistor. A control trench electrode of at least one control trench gate is electrically connected to a gate electrode of the transistor.Type: ApplicationFiled: March 9, 2022Publication date: December 29, 2022Applicant: Mitsubishi Electric CorporationInventors: Shinya Soneda, Kazuya Konishi, Akihiko Furukawa
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Publication number: 20220310829Abstract: There is provided a technique capable of reducing turn-on power losses. A semiconductor device includes: a semiconductor substrate including a drift layer; and a base layer, a contact layer, and a source layer which are provided in the semiconductor substrate. A gate portion is provided in a first trench, with a first gate insulation film therebetween. The first trench is in contact with the contact layer, the source layer, the base layer, and the drift layer. The gate portion is provided with a recessed portion with a bottom farther away from the base layer than a side thereof. A first insulation portion is provided in the recessed portion of the gate portion in the first trench.Type: ApplicationFiled: December 6, 2021Publication date: September 29, 2022Applicant: Mitsubishi Electric CorporationInventors: Kazuya KONISHI, Shinya SONEDA, Koichi NISHI, Tetsuya NITTA, Akihiko FURUKAWA
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Publication number: 20220302289Abstract: Hysteresis of gate leakage is reduced in a semiconductor device with a structure including embedded electrodes below gate trench electrodes. A semiconductor device includes an active trench gate formed in a trench coming in contact with an emitter layer, a base layer, and a carrier storage layer to reach a drift layer. The active trench gate includes: a gate trench insulating film formed on an inner wall of the trench; and a gate trench electrode, and an embedded electrode below the gate trench electrode, the gate trench electrode and the embedded electrode being formed on the gate trench insulating film in the trench and being insulated from each other. The embedded electrode is lower in phosphorus concentration than the gate trench electrode.Type: ApplicationFiled: January 4, 2022Publication date: September 22, 2022Applicant: Mitsubishi Electric CorporationInventors: Koichi NISHI, Shinya SONEDA, Akihiko FURUKAWA, Katsumi NAKAMURA
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Publication number: 20220262934Abstract: Examples of a semiconductor device includes a transistor region formed in a semiconductor substrate having a first conductivity type drift layer, and a diode region formed to be adjacent to the transistor region in the semiconductor substrate, wherein the diode region has a second conductivity type anode layer formed on the drift layer and a first conductivity type cathode layer formed on the lower side of the drift layer, and the cathode layer has an adjacent region contacting the transistor region, the adjacent region having a depth, from a lower surface of the semiconductor substrate, which becomes shallower toward the transistor region and having first conductivity type impurity concentration which decreases toward the transistor region.Type: ApplicationFiled: May 3, 2022Publication date: August 18, 2022Applicant: Mitsubishi Electric CorporationInventors: Ryu KAMIBABA, Tetsuo TAKAHASHI, Akihiko FURUKAWA
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Patent number: 11398563Abstract: Examples of a semiconductor device includes a transistor region formed in a semiconductor substrate having a first conductivity type drift layer, and a diode region formed to be adjacent to the transistor region in the semiconductor substrate, wherein the diode region has a second conductivity type anode layer formed on the drift layer and a first conductivity type cathode layer formed on the lower side of the drift layer, and the cathode layer has an adjacent region contacting the transistor region, the adjacent region having a depth, from a lower surface of the semiconductor substrate, which becomes shallower toward the transistor region and having first conductivity type impurity concentration which decreases toward the transistor region.Type: GrantFiled: December 19, 2018Date of Patent: July 26, 2022Assignee: Mitsubishi Electric CorporationInventors: Ryu Kamibaba, Tetsuo Takahashi, Akihiko Furukawa
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Publication number: 20220190146Abstract: A semiconductor device includes a first contact layer connected to a lower portion of a first trench contact portion and a second contact layer connected to a lower portion of a second trench contact portion. The distance between a first side portion of a first trench and the first trench contact portion is larger than that between a second side portion of the first trench and the second trench contact portion in a plan view, and the first contact layer is separated from the first side portion and the second contact layer is connected to the second side portion in a cross section. With this structure, it is possible to provide a technique for achieving an appropriate channel region.Type: ApplicationFiled: October 1, 2021Publication date: June 16, 2022Applicant: Mitsubishi Electric CorporationInventors: Kazuya KONISHI, Shinya SONEDA, Tetsuya NITTA, Akihiko FURUKAWA
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Patent number: 11349020Abstract: A semiconductor device that includes transistor and diode regions in one semiconductor substrate achieves favorable tolerance during recovery behaviors of diodes. A semiconductor base includes an n?-type drift layer in the IGBT and diode regions. In the IGBT region, the semiconductor base includes a p-type base layer formed on the n?-type drift layer, a p+-type diffusion layer and an n+-type emitter layer formed selectively on the p-type base layer, the diffusion layer having a higher p-type impurity concentration than the p-type base layer, and gate electrodes facing the p-type base layer via a gate insulating film. In the diode region, the semiconductor base includes a p?-type anode layer formed on the n?-type drift layer. The p+-type diffusion layer has a higher p-type impurity concentration than the p?-type anode layer, and has a smaller depth and a lower p-type impurity concentration as approaching the diode region.Type: GrantFiled: May 21, 2020Date of Patent: May 31, 2022Assignee: Mitsubishi Electric CorporationInventors: Ryu Kamibaba, Tetsuo Takahashi, Akihiko Furukawa
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Publication number: 20220157976Abstract: A semiconductor device includes; a semiconductor substrate; an emitter electrode provided on the semiconductor substrate; a gate electrode provided on the semiconductor substrate; a drift layer of a first conduction type provided in the semiconductor substrate; a source layer of the first conduction type provided on an upper surface side of the semiconductor substrate; a base layer of a second conduction type provided on the upper surface side of the semiconductor substrate; a collector electrode provided below the semiconductor substrate; and a two-part dummy active trench including, at an upper part, an upper dummy part not connected with the gate electrode and including, at a lower part, a lower active part connected with the gate electrode and covered by an insulating film, in a trench of the semiconductor substrate, wherein a longitudinal length of the lower active part is larger than a width of the lower active part.Type: ApplicationFiled: June 28, 2021Publication date: May 19, 2022Applicant: Mitsubishi Electric CorporationInventors: Kazuya KONISHI, Koichi NISHI, Akihiko FURUKAWA
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Patent number: 11282950Abstract: Provided is a technology for obtaining a drain current of a sufficient magnitude in a field effect transistor using a nitride semiconductor. A channel layer that is Alx1Iny1Ga1-x1-y1N is formed on an upper surface of a semiconductor substrate, and on an upper surface of the channel layer, a barrier layer that is Alx2Iny2Ga1-x2-y2N having a band gap larger than that of the channel layer is formed. Then, on an upper surface of the barrier layer, a gate insulating film that is an insulator or a semiconductor and has a band gap larger than that of the barrier layer is at least partially formed, and a gate electrode is formed on an upper surface of the gate insulating film. Then, heat treatment is performed while a positive voltage is applied to the gate electrode.Type: GrantFiled: May 31, 2017Date of Patent: March 22, 2022Assignee: MITSUBISHI ELECTRIC CORPORATIONInventors: Takuma Nanjo, Tetsuro Hayashida, Koji Yoshitsugu, Akihiko Furukawa
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Patent number: 11222985Abstract: An n-type semiconductor layer has a single-crystal structure and is made of a wide-gap semiconducting material. A p-type semiconductor layer is provided on the n-type semiconductor layer and made of a material different from the aforementioned wide-gap semiconducting material, and has either a microcrystalline structure or an amorphous structure. An electrode is provided on at least one of the n-type semiconductor layer and the p-type semiconductor layer.Type: GrantFiled: February 14, 2017Date of Patent: January 11, 2022Assignees: Mitsubishi Electric Corporation, Tokyo Institute of TechnologyInventors: Tatsuro Watahiki, Yohei Yuda, Akihiko Furukawa, Shinsuke Miyajima, Yuki Takiguchi
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Patent number: 10971634Abstract: An oxide semiconductor device has an improved withstand voltage when an inverse voltage is applied, while suppressing diffusion of different types of materials to a Schottky interface. The oxide semiconductor device includes an n-type gallium oxide epitaxial layer, p-type oxide semiconductor layers of an oxide that is a different material from the material for the gallium oxide epitaxial layer, a dielectric layer formed to cover at least part of a side surface of the oxide semiconductor layer, an anode electrode, and a cathode electrode. Hetero pn junctions are formed between the lower surfaces of the oxide semiconductor layers and a gallium oxide substrate or between the lower surfaces of the oxide semiconductor layers and the gallium oxide epitaxial layer.Type: GrantFiled: June 8, 2018Date of Patent: April 6, 2021Assignee: MITSUBISHI ELECTRIC CORPORATIONInventors: Yohei Yuda, Tatsuro Watahiki, Akihiko Furukawa
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Patent number: 10892352Abstract: In the present application, a power semiconductor device includes a first-conductive-type first base region having a first principal surface and a second principal surface opposite to the first principal surface, a second-conductive-type second base region disposed on the first principal surface and at least three groove parts parallel to each other disposed from a surface of the second base region. The device further includes insulating films covering inner walls of the respective groove parts, conductive trench gates filled on the insulating films, a first-conductive-type emitter region disposed in the second base region, and a second-conductive-type collector region disposed on the second principal surface of the first base region. The trench gates embedded in the first groove part and the third groove part are electrically connected to the gate electrode, and the trench gate embedded in the second groove part is electrically connected to the emitter electrode.Type: GrantFiled: December 6, 2018Date of Patent: January 12, 2021Assignee: MITSUBISHI ELECTRIC CORPORATIONInventors: Akihiko Furukawa, Shoichi Orita, Hiroki Muraoka, Atsushi Narazaki, Tsuyoshi Kawakami, Yuji Murakami