Patents by Inventor Hiroyasu Hagino
Hiroyasu Hagino 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: 5489788Abstract: In an insulated gate semiconductor device, a loss is suppressed and a short-circuit tolerance as well as a latch-up tolerance are improved. A saturation current I.sub.CE (sat) and a short-circuit tolerance tw are reduced without much influencing a collector-emitter saturation voltage V.sub.CE (sat) by setting a sheet resistance of an n-type emitter region 4 at a large value. When the sheet resistance is in the range between 40.OMEGA./.quadrature. and 150.OMEGA./.quadrature., 10 .mu.sec or more of the short-circuit tolerance, which is practically sufficient, is ensured while the collector-emitter saturation voltage V.sub.CE (sat) is suppressed to practically small 2.4 V or less. Both the collector-emitter saturation voltage V.sub.CE (sat) and the saturation current I.sub.CE (sat) are restrained small, thereby realizing an enhanced short-circuit tolerance.Type: GrantFiled: March 7, 1994Date of Patent: February 6, 1996Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Yoshifumi Tomomatsu, Hiroshi Yamaguchi, Hiroyasu Hagino
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Patent number: 5451531Abstract: An improved insulated gate semiconductor device comprises a high-concentration p-type semiconductor region formed widely enough to protrude over n-type emitter regions without reaching an n-type epitaxial layer over a p-type base region only in first regions wherein the n-type emitter regions are wider than second regions as viewed from the top of the device. A gate threshold voltage V.sub.GE (th) has a relatively high level V.sub.GE (th-High) in the first regions, so that a low collector-emitter saturation voltage V.sub.CE (sat) and a low saturation current I.sub.CE (sat) are achieved. This provides for a high short-circuit tolerance as well as a high latch-up tolerance with low losses.Type: GrantFiled: March 22, 1994Date of Patent: September 19, 1995Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Hiroshi Yamaguchi, Hiroyasu Hagino, Yoshifumi Tomomatsu
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Patent number: 5391898Abstract: An IGBT has an emitter bypass structure. The interval D between N emitter regions is adapted to be larger than two times of a channel length L in order to effectively decrease a channel width to effectively decrease a saturation current. A high concentration region may be provided in a P base region, which is closer to the end portion of the P base region than the emitter regions between the emitter regions, so that the channel width can be effectively decreased even without the relation of D>2L. A channel width per unit area W.sub.U may be in a range of 140 cm.sup.-1 .ltoreq.W.sub.U .ltoreq.280 cm.sup.-1 in an IGBT of a breakdown voltage class of 500-750 V or 70 cm.sup.-1 .ltoreq.W.sub.U .ltoreq.150 cm.sup.-1 in an IGBT of a breakdown voltage class of 1000-1500 V, so that an IGBT having a short-circuit withstandability and a latch-up withstandability suitable for an inverter can be implemented.Type: GrantFiled: August 10, 1992Date of Patent: February 21, 1995Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Hiroyasu Hagino
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Patent number: 5380670Abstract: An N.sup.+ buffer layer (2) and an N.sup.- layer (3) are provided on a P.sup.+ silicon substrate (1) in this order. On an upper portion of the N.sup.- layer (3), a P.sup.- layer (4b) is selectively formed, and on the P.sup.- layer (4b), a P.sup.+ layer (4a) is provided. On part of a top surface of the P.sup.+ layer (4a), a plurality of N.sup.+ layers (5a) are provided, and a trench (13) is formed extending through each of the N.sup.+ layers (5a) and P.sup.+ layer (4a) downwards to the P.sup.- layer (4b). In the P.sup.- layer (4b), an N.sup.+ floating layer (5b) is provided covering the bottom face of each trench (13). In the inner hollow of the trench (13), a gate electrode (8a) is provided through a gate oxidation film (7a), while an emitter electrode (9a) is provided extending between the top surfaces of the adjacent N.sup.+ layers (5a) with the surface of the P.sup.+ layer (4a) interposed so as to electrically short circuit them. A collector electrode (10) is provided on a lower major surface of the P.sup.Type: GrantFiled: February 2, 1994Date of Patent: January 10, 1995Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Hiroyasu Hagino
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Patent number: 5321281Abstract: An improved insulated gate semiconductor device comprises a high-concentration p-type semiconductor region formed widely enough to protrude over n-type emitter regions without reaching an n-type epitaxial layer over a p-type base region only in first regions wherein the n-type emitter regions are wider than second regions as viewed from the top of the device. A gate threshold voltage V.sub.GE (th) has a relatively high level V.sub.GE (th-High) in the first regions, so that a low collector-emitter saturation voltage V.sub.CE (sat) and a low saturation current I.sub.CE (sat) are achieved. This provides for a high short-circuit tolerance as well as a high latch-up tolerance with low losses.Type: GrantFiled: March 8, 1993Date of Patent: June 14, 1994Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Hiroshi Yamaguchi, Hiroyasu Hagino, Yoshifumi Tomomatsu
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Patent number: 5304821Abstract: An N.sup.+ buffer layer (2) and an N.sup.- layer (3) are provided on a P.sup.+ silicon substrate (1) in this order. On an upper portion of the N.sup.- layer (3), a P.sup.- layer (4b) is selectively formed, and on the P.sup.- layer (4b), a P.sup.+ layer (4a) is provided. On part of an top surface of the P.sup.+ layer (4a), a plurality of N.sup.+ layers (5a) are provided, and a trench (13) is formed extending through each of the N.sup.+ layers (5a) and P.sup.+ layer (4a) downwards to the P.sup.- layer (4b). In the P.sup.- layer (4b), an N.sup.+ floating layer (5b) is provided covering the bottom face of each trench (13). In the inner hollow of the trench (13), a gate electrode (8a) is provided through a gate oxidation film (7a), while an emitter electrode (9a) is provided extending between the top surfaces of the adjacent N.sup.+ layers (5a) with the surface of the P.sup.+ layer (4a) interposed so as to electrically short circuit them. A collector electrode (10) is provided on a lower major surface of the P.Type: GrantFiled: September 30, 1991Date of Patent: April 19, 1994Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Hiroyasu Hagino
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Patent number: 5171696Abstract: The present invention direct to a semiconductor device and a method of manufacturing the same. According to the semiconductor device of the present invention, a first region is partially formed on a major surface of a semiconductor substrate so as to have the opposite conductivity to the first region, and an electrode is formed on the major surface. A barrier layer may be formed between the region adjacent to the first region of the semiconductor substrate and the electrode in order to reduce a current flowing in a parasitic diode. Or, an area of a connecting part between the first region and the electrode may be set to be larger than that of a connecting part between the region adjacent to the first region of the semiconductor substrate and the electrode in order to reduce a current flowing in a parasitic diode. Or, both of technique mentioned above may be combined to reduce a current flowing in a parasitic diode. Thus, it is possible to provide a semiconductor device which can be fit for high-frequency use.Type: GrantFiled: November 20, 1991Date of Patent: December 15, 1992Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Hiroyasu Hagino
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Patent number: 5170239Abstract: An IGBT has an emitter bypass structure. The interval D between N emitter regions is adapted to be larger than two times of a channel length L in order to effectively decrease a channel width to effectively decrease a saturation current. A high concentration region may be provided in a P base region, which is closer to the end portion of the P base region than the emitter regions between the emitter regions, so that the channel width can be effectively decreased even without the relation of D>2L. A channel width per unit area W.sub.U may be in a range of 140 cm.sup.-1 .ltoreq.W.sub.U .ltoreq.280 cm.sup.-1 in an IGBT of a breakdown voltage class of 500-750 V or 70 cm.sup.-1 .ltoreq.W.sub.U .ltoreq.150 cm.sup.-1 in an IGBT of a breakdown voltage class of 1000-1500 V, so that an IGBT having a short-circuit withstandability and a latch-up withstandability suitable for an inverter can be implemented.Type: GrantFiled: January 31, 1991Date of Patent: December 8, 1992Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Hiroyasu Hagino
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Patent number: 5086324Abstract: The present invention direct to a semiconductor device and a method of manufacturing the same. According to the semiconductor device of the present invention, a first region is partially formed on a major surface of a semiconductor substrate so as to have the opposite conductivity to the first region, and an electrode is formed on the major surface. A barrier layer may be formed between the region adjacent to the first region of the semiconductor substrate and the electrode in order to reduce a current flowing in a parasitic diode. Or, an area of a connecting part between the first region and the electrode may be set to be larger than that of a connecting part between the region adjacent to the first region of the semiconductor substrate and the electrode in order to reduce a current flowing in a parasitic diode. Or, both of technique mentioned above may be combined to reduce a current flowing in a parasitic diode. Thus, it is possible to provide a semiconductor device which can be fit for high-frequency use.Type: GrantFiled: April 21, 1989Date of Patent: February 4, 1992Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Hiroyasu Hagino
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Patent number: 5084401Abstract: A P-type base region, which is formed on an N-type body layer, as a relatively deep first base region and a relatively shallow second base region. An N.sup.+ -type emitter region is formed on the base region. A portion of the surface of the second base region between surfaces of the emitter region and body layer is defined as a channel. A gate oxide film, on which a gate electrode is formed, is provided on the channel. The amount and depth of introduction of an impurity in the second base region is about 2.times.10.sup.14 to 5.times.10.sup.14 cm.sup.-2 and 4 to 10 .mu.m, respectively. The thickness of the gate oxide film is about 600 to 1000 .ANG.. Thus, an IGBT is implemented, which can ensure sufficient pulse energization ability while causing no latch-up in application to a stroboscope circuit.Type: GrantFiled: December 17, 1990Date of Patent: January 28, 1992Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Hiroyasu Hagino
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Patent number: 5023691Abstract: An IGBT has an emitter bypass structure. The interval D between N emitter regions is adapted to be larger than two times of a channel length L in order to effectively decrease a channel width to effectively decrease a saturation current. A high concentration region may be provided in a P base region, which is closer to the end portion of the P base region than the emitter regions between the emitter regions, so that the channel width can be effectively decreased even without the relation of D>2L. A channel width per unit area W.sub.U may be in a range of 140 cm.sup.-1 .ltoreq.W.sub.U .ltoreq.280 cm.sup.-1 in an IGBT of a breakdown voltage class of 500-750 V or 70 cm.sup.-1 .ltoreq.W.sub.U .ltoreq.150 cm.sup.-1 in an IGBT of a breakdown voltage class of 1000-1500 V, so that an IGBT having a short-circuit withstandability and a latch-up withstandability suitable for an inverter can be implemented.Type: GrantFiled: September 1, 1989Date of Patent: June 11, 1991Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Hiroyasu Hagino
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Patent number: 4990975Abstract: A P-type base region, which is formed on an N-type body layer, has a relatively deep first base region and a relatively shallow second base region. An N.sup.+ -type emitter region is formed on the base region. A portion of the surface of the second base region between surfaces of the emitter region and body layer is defined as a channel. A gate oxide film, on which a gate electrode is formed, is provided on the channel. The amount and depth of introduction of an impurity in the second base region is about 2.times.10.sup.14 to 5.times.10.sup.14 cm.sup.-2 and 4 to 10 .mu.m, respectively. The thickness of the gate oxide film is about 600 to 1000 .ANG.. Thus, an IGBT is implemented, which can ensure sufficient pulse energization ability while causing no latch-up in application to a stroboscope circuit.Type: GrantFiled: April 21, 1989Date of Patent: February 5, 1991Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Hiroyasu Hagino
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Patent number: 4662957Abstract: A method of producing a gate turn-off thyristor includes producing a first n type impurity region, a second p type impurity region, a third n type impurity region, and a fourth p type impurity region produced in a semiconductor substrate providing a cathode electrode in contact with the first n type impurity region, providing a gate electrode in contact with the second p type impurity region, and an anode electrode which short-circuits the third and the fourth regions at the second main surface of the semiconductor substrate. Gold is diffused into the third region at a predetermined diffusion temperature thereby shortening the life time of carriers in the substrate.Type: GrantFiled: April 22, 1985Date of Patent: May 5, 1987Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Hiroyasu Hagino
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Patent number: 4556898Abstract: A semiconductor device includes a semiconductor element (21) having a cathode (21d) divided into a plurality of islands, each of the cathode islands (21d) being electrically connected through a cathode insert (24). The cathode insert (24) comprises a cup-shaped first conductor (241, 245) and a second conductor (242, 246) fitted into and kept in electrical contact with the first conductor (241, 245). The cup-shaped first conductor (241, 245) is disposed such that its bottom is in electrical contact with the plurality of the cathode islands (21d). The cathode side of the semiconductor element (21) is pressed against the anode side thereof for good liberation of heat.Type: GrantFiled: December 27, 1983Date of Patent: December 3, 1985Assignee: Mitsubishi Denki Kabushiki KaishaInventor: Hiroyasu Hagino
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Patent number: 4001873Abstract: A polycrystalline silicon film is disposed on the face of an N type silicon substrate including a termination of a PN junction to extend slightly beyond the termination of the PN junction from the periphery of the substrate. In the most preferred embodiment, the polycrystalline silicon film terminates short of both the termination of the PN junction and the periphery of the substrate and is enclosed with silicon dioxide, the silicon dioxide being also disposed at the termination of the PN junction and on the adjacent portions of the main substrate face on its both side as well as on the periphery of the main face.Type: GrantFiled: December 23, 1974Date of Patent: January 4, 1977Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Yasuya Kajiwara, Seiichi Nagai, Hiroyasu Hagino
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Patent number: 3933541Abstract: A silicon dioxide film and a silicon nitride film are successively vapor-deposited on a main face of an N type silicon substrate processed with H.sub.2 O.sub.2 water. Those portions of both films underlaid by a P type region to be subsequently formed and their peripheral portions are selectively removed. Then a P type impurity is diffused into the central exposed portion of the main substrate face to form the P type region with a PN junction having a termination facing the silicon dioxide film. Also a silicon dioxide film is thermally formed on the peripheral exposed portion of the main face.Type: GrantFiled: January 20, 1975Date of Patent: January 20, 1976Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Hiroyasu Hagino, Yasuya Kajiwara, Seiichi Nagai