Patents by Inventor Tomoyoshi Kushida
Tomoyoshi Kushida 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: 10680091Abstract: In a semiconductor device having a heterojunction type superjunction structure, a drain portion and a source portion are electrically connected to one of a two-dimensional electron gas layer and a two-dimensional hole gas layer, and a gate portion is prevented by an insulating region from directly contacting the one of the two-dimensional election gas layer and the two-dimensional hole gas layer.Type: GrantFiled: December 21, 2018Date of Patent: June 9, 2020Assignees: Toyota Jidosha Kabushiki Kaisha, Toyota School FoundationInventors: Tomoyoshi Kushida, Yoshitaka Nagasato, Naotaka Iwata, Hiroyuki Sakaki
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Publication number: 20190198652Abstract: In a semiconductor device having a heterojunction type superjunction structure, a drain portion and a source portion are electrically connected to one of a two-dimensional electron gas layer and a two-dimensional hole gas layer, and a gate portion is prevented by an insulating region from directly contacting the one of the two-dimensional election gas layer and the two-dimensional hole gas layer.Type: ApplicationFiled: December 21, 2018Publication date: June 27, 2019Applicants: Toyota Jidosha Kabushiki Kaisha, Toyota School FoundationInventors: Tomoyoshi Kushida, Yoshitaka Nagasato, Naotaka Iwata, Hiroyuki Sakaki
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Patent number: 9653621Abstract: A semiconductor apparatus (10) includes: a layered structure (100) that includes double junction structures that have a first junction (151, 153) where a wide-bandgap layer (102, 104) and a narrow-bandgap layer (101, 103, 105) are layered on each other and a second junction (152, 154) where a narrow-bandgap layer (101, 103, 105) and a wide-bandgap layer (102, 104) are layered on each other, and electrode semiconductor layers (110, 120) are joined to each layer of the layered structure. Each double junction structure includes a pair of a first region (131, 133) that has negative fixed charge and a second region (132, 134) that has positive fixed charge. The first region is closer to the first junction than to a center of the wide-bandgap layer. The second region is closer to the second junction than to the center of the wide-bandgap layer. A 2DEG or a 2DHG is formed at each junction. The semiconductor apparatus functions as an electric energy storage device such as a capacitor.Type: GrantFiled: March 14, 2013Date of Patent: May 16, 2017Assignees: TOYOTA JIDOSHA KABUSHIKI KAISHA, TOYOTA SCHOOL FOUNDATIONInventors: Tomoyoshi Kushida, Hiroyuki Sakaki, Masato Ohmori
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Publication number: 20150108609Abstract: A semiconductor apparatus (10) includes: a layered structure (100) that includes double junction structures that have a first junction (151, 153) where a wide-bandgap layer (102, 104) and a narrow-bandgap layer (101, 103, 105) are layered on each other and a second junction (152, 154) where a narrow-bandgap layer (101, 103, 105) and a wide-bandgap layer (102, 104) are layered on each other, and electrode semiconductor layers (110, 120) are joined to each layer of the layered structure. Each double junction structure includes a pair of a first region (131, 133) that has negative fixed charge and a second region (132, 134) that has positive fixed charge. The first region is closer to the first junction than to a center of the wide-bandgap layer. The second region is closer to the second junction than to the center of the wide-bandgap layer. A 2DEG or a 2DHG is formed at each junction. The semiconductor apparatus functions as an electric energy storage device such as a capacitor.Type: ApplicationFiled: March 14, 2013Publication date: April 23, 2015Applicants: TOYOTA SCHOOL FOUNDATION, TOYOTA JIDOSHA KABUSHIKI KAISHAInventors: Tomoyoshi Kushida, Hiroyuki Sakaki, Masato Ohmori
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Patent number: 8830114Abstract: A mobile object detecting apparatus includes first radiation detecting means; and second radiation detecting means for radiating an electromagnetic wave having the same frequency as the electromagnetic wave radiated by the first radiation detecting means such that the radiated electromagnetic wave passes near a point in the first radiation detecting means from which the electromagnetic wave is radiated, and detecting a standing wave which is generated due to reflection of the radiated electromagnetic wave at an object; wherein a distance, over which the electromagnetic wave radiated by the first radiation detecting means travels until it reaches near the first radiation detecting means, corresponds to a distance of an integral multiple of a wave length of a half cycle of the electromagnetic waves radiated by the radiation detecting means plus a wave length of a predetermined period which is smaller than the half cycle.Type: GrantFiled: September 30, 2010Date of Patent: September 9, 2014Assignee: Toyota Jidosha Kabushiki KaishaInventors: Tomoyoshi Yasue, Tomoyoshi Kushida
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Publication number: 20120235850Abstract: A mobile object detecting apparatus includes first radiation detecting means ; and second radiation detecting means for radiating an electromagnetic wave having the same frequency as the electromagnetic wave radiated by the first radiation detecting means such that the radiated electromagnetic wave passes near a point in the first radiation detecting means from which the electromagnetic wave is radiated, and detecting a standing wave which is generated due to reflection of the radiated electromagnetic wave at an object; wherein a distance, over which the electromagnetic wave radiated by the first radiation detecting means travels until it reaches near the first radiation detecting means, corresponds to a distance of an integral multiple of a wave length of a half cycle of the electromagnetic waves radiated by the radiation detecting means plus a wave length of a predetermined period which is smaller than the half cycle.Type: ApplicationFiled: September 30, 2010Publication date: September 20, 2012Inventors: Tomoyoshi Yasue, Tomoyoshi Kushida
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Patent number: 7569914Abstract: With conventional device, the quantity of complex defects differs with each semiconductor device because the concentration of impurities intrinsically contained differs for each silicon wafer. Consequently, there is an undesirable variation in characteristics among the semiconductor devices. The invention provides a method for manufacturing PIN type diode which comprises an intermediate semiconductor region in which complex defects are formed. The method comprises introducing impurities (for example, carbon), which are the same kind of impurities intrinsically contained in the intermediate semiconductor region, into the intermediate semiconductor region, and irradiating the intermediate semiconductor region with helium ions to form point defects.Type: GrantFiled: September 27, 2007Date of Patent: August 4, 2009Assignee: Toyota Jidosha Kabushiki KaishaInventors: Shinya Yamazaki, Tomoyoshi Kushida, Takahide Sugiyama
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Patent number: 7507646Abstract: With conventional device, the quantity of complex defects differs with each semiconductor device because the concentration of impurities intrinsically contained differs for each silicon wafer. Consequently, there is an undesirable variation in characteristics among the semiconductor devices. The invention provides a method for manufacturing PIN type diode which comprises an intermediate semiconductor region in which complex defects are formed. The method comprises introducing impurities (for example, carbon), which are the sane kind of impurities intrinsically contained in the intermediate semiconductor region, into the intermediate semiconductor region, and irradiating the intermediate semiconductor region with helium ions to form point defects.Type: GrantFiled: May 19, 2006Date of Patent: March 24, 2009Assignee: Toyota Jidosha Kabushiki KaishaInventors: Shinya Yamazaki, Tomoyoshi Kushida, Takahide Sugiyama
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Publication number: 20080023795Abstract: With conventional device, the quantity of complex defects differs with each semiconductor device because the concentration of impurities intrinsically contained differs for each silicon wafer. Consequently, there is an undesirable variation in characteristics among the semiconductor devices. The invention provides a method for manufacturing PIN type diode which comprises an intermediate semiconductor region in which complex defects are formed. The method comprises introducing impurities (for example, carbon), which are the same kind of impurities intrinsically contained in the intermediate semiconductor region, into the intermediate semiconductor region, and irradiating the intermediate semiconductor region with helium ions to form point defects.Type: ApplicationFiled: September 27, 2007Publication date: January 31, 2008Inventors: Shinya YAMAZAKI, Tomoyoshi KUSHIDA, Takahide SUGIYAMA
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Publication number: 20060281263Abstract: With conventional device, the quantity of complex defects differs with each semiconductor device because the concentration of impurities intrinsically contained differs for each silicon wafer. Consequently, there is an undesirable variation in characteristics among the semiconductor devices. The invention provides a method for manufacturing PIN type diode which comprises an intermediate semiconductor region in which complex defects are formed. The method comprises introducing impurities (for example, carbon), which are the sane kind of impurities intrinsically contained in the intermediate semiconductor region, into the intermediate semiconductor region, and irradiating the intermediate semiconductor region with helium ions to form point defects.Type: ApplicationFiled: May 19, 2006Publication date: December 14, 2006Inventors: Shinya Yamazaki, Tomoyoshi Kushida, Takahide Sugiyama
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Patent number: 7038275Abstract: An object of this invention is to provide a buried gate-type semiconductor device in which its gate interval is minimized so as to improve channel concentration thereby realizing low ON-resistance, voltage-resistance depression due to convergence of electrical fields in the vicinity of the bottom of the gate is prevented and further prevention of voltage-resistance depression and OFF characteristic are achieved at the same time. A plurality of gate electrodes 106 each having a rectangular section are disposed in its plan section. The interval 106T between the long sides of the gate electrodes 106 is made shorter than the interval 106S between the short sides thereof. Further, a belt-like contact opening 108 is provided between the short sides of the gate electrode 106, so that P+ source region 100 and N+ source region 104 are in contact with a source electrode. Consequently, the interval 106T between the long sides of the gate electrode 106 can be set up regardless of the width of the contact opening 108.Type: GrantFiled: December 11, 2003Date of Patent: May 2, 2006Assignee: Toyota Jidosha Kabushiki KaishaInventor: Tomoyoshi Kushida
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Patent number: 6930353Abstract: It is intended to provide a field-effective-type semiconductor device that can let low ON-resistance and non-excessive short-circuit current go together by effectively using its channel width and prevents device from destruction. In a field-effective-type semiconductor device, a semiconductor region arranged between gate electrodes 106 has stripe-patterned structure consisting of an N+ emitter region 104 and a P emitter region. The P emitter region is constituted by P channel region 103 of low concentration and P+ emitter region 100 of high concentration. The N+ emitter region 104, the P channel region 103, and the P+ emitter region 100 are in contact with the emitter electrode 109. Thereby, a channel width X is limited to the extent that is enough for ON current under normal operation state. That is, low ON-resistance and not excessive short-circuit current can go together in the field-effective-type semiconductor device.Type: GrantFiled: October 29, 2003Date of Patent: August 16, 2005Assignee: Toyota Jidosha Kabushiki KaishaInventors: Katsuhiko Nishiwaki, Tomoyoshi Kushida
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Patent number: 6921941Abstract: It is intended to provide a high withstand voltage field effect type semiconductor device that relaxes electric fields in a semiconductor substrate without thickening thickness of a drift region and achieves withstand-ability against high voltage without sacrificing ON-voltage, switch-OFF characteristics, and miniaturization. A field effective type semiconductor device comprises emitter regions 100, 104 and gate electrodes 106 and the like on a surface (upper surface in FIG. 2), a collector region 101 and the like on the other surface (lower surface in FIG. 2), wherein N? field dispersion regions 111 of low impurity concentration are arranged between P body regions 103 facing to gate electrodes 106 and an N drift region 102 below P body regions 103. Thereby, electric field between collector and emitter is relaxed and high withstand voltage field effect type semiconductor device is realized.Type: GrantFiled: February 13, 2004Date of Patent: July 26, 2005Assignee: Toyota Jidosha Kabushiki KaishaInventors: Katsuhiko Nishiwaki, Tomoyoshi Kushida, Sachiko Kawaji
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Patent number: 6855983Abstract: A trench gate type semiconductor device has an ON resistance that has been reduced. The device has a drain electrode on one side of the substrate and has a drift region, channel region, source region, and a source electrode on the other side. The channel region is sandwiched between a trench gate region covered with insulating film. Current passes when a positive bias voltage is applied to the trench region, and current is cut off when a negative bias voltage is applied.Type: GrantFiled: November 8, 1999Date of Patent: February 15, 2005Assignee: Toyota Jidosha Kabushiki KaishaInventor: Tomoyoshi Kushida
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Publication number: 20040164349Abstract: It is intended to provide a high withstand voltage field effect type semiconductor device that relaxes electric fields in a semiconductor substrate without thickening thickness of a drift region and achieves withstand-ability against high voltage without sacrificing ON-voltage, switch-OFF characteristics, and miniaturization. A field effective type semiconductor device comprises emitter regions 100, 104 and gate electrodes 106 and the like on a surface (upper surface in FIG. 2), a collector region 101 and the like on the other surface (lower surface in FIG. 2), wherein N− field dispersion regions 111 of low impurity concentration are arranged between P body regions 103 facing to gate electrodes 106 and an N drift region 102 below P body regions 103. Thereby, electric field between collector and emitter is relaxed and high withstand voltage field effect type semiconductor device is realized.Type: ApplicationFiled: February 13, 2004Publication date: August 26, 2004Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHAInventors: Katsuhiko Nishiwaki, Tomoyoshi Kushida, Sachiko Kawaji
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Patent number: 6774407Abstract: The present invention provides a semiconductor device wherein the turning-off time thereof can be reduced substantially and, at the same time, the turned-on resistance thereof can also be prevented effectively from increasing as well. Lattice defects are distributed at a high concentration in a defect region an area in close proximity to the boundary surface between an n drift region and a p+ substrate. The half-value width of the distribution is set at a value which is large enough for the defect region to include a non-depletion region in the n drift region. However, the defect region is not spread to cover a diffusion layer. In this way, the turning-off time of the semiconductor device can be reduced considerably without being accompanied by an increase in turned-on resistance thereof. In addition, by employing an absorber with an uneven surface, the distribution of lattice defects can be obtained by carrying out radiation of ions at only one time.Type: GrantFiled: January 2, 2001Date of Patent: August 10, 2004Assignee: Toyota Jidosha Kabushiki KaishaInventor: Tomoyoshi Kushida
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Publication number: 20040119117Abstract: An object of this invention is to provide a buried gate-type semiconductor device in which its gate interval is minimized so as to improve channel concentration thereby realizing low ON-resistance, voltage-resistance depression due to convergence of electrical fields in the vicinity of the bottom of the gate is prevented and further prevention of voltage-resistance depression and OFF characteristic are achieved at the same time. A plurality of gate electrodes 106 each having a rectangular section are disposed in its plan section. The interval 106T between the long sides of the gate electrodes 106 is made shorter than the interval 106S between the short sides thereof. Further, a belt-like contact opening 108 is provided between the short sides of the gate electrode 106, so that P+ source region 100 and N+ source region 104 are in contact with a source electrode.Type: ApplicationFiled: December 11, 2003Publication date: June 24, 2004Applicant: Toyoda Jidosha Kabushiki KaishaInventor: Tomoyoshi Kushida
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Publication number: 20040084725Abstract: It is intended to provide a field-effective-type semiconductor device that can let low ON-resistance and non-excessive short-circuit current go together by effectively using its channel width and prevents device from destruction. In a field-effective-type semiconductor device, a semiconductor region arranged between gate electrodes 106 has stripe-patterned structure consisting of an N+ emitter region 104 and a P emitter region. The P emitter region is constituted by P channel region 103 of low concentration and P+ emitter region 100 of high concentration. The N+ emitter region 104, the P channel region 103, and the P+ emitter region 100 are in contact with the emitter electrode 109. Thereby, a channel width X is limited to the extent that is enough for ON current under normal operation state. That is, low ON-resistance and not excessive short-circuit current can go together in the field-effective-type semiconductor device.Type: ApplicationFiled: October 29, 2003Publication date: May 6, 2004Applicant: Toyota Jidosha Kabushiki KaishaInventors: Katsuhiko Nishiwaki, Tomoyoshi Kushida
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Patent number: 6518629Abstract: In a semiconductor device having high voltage resistance and low ON voltage characteristics, charge-storage regions (insulation layer) are formed in a drift region. Formed above the drift region are a channel region, an emitter region, trench-type gate electrodes, and an emitter electrode. Strips of the insulation layer extend in a direction intersecting a direction of extension of the gate electrodes, and form a stripe pattern. The insulation layer curbs extraction of holes into the channel region. Openings in the stripe pattern of the insulation layer form depletion layers.Type: GrantFiled: July 3, 2000Date of Patent: February 11, 2003Assignee: Toyota Jidosha Kabushiki KaishaInventors: Tomoyoshi Kushida, Katsuhiko Nishiwaki
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Publication number: 20010011745Abstract: The present invention provides a semiconductor device wherein the turning-off time thereof can be reduced substantially and, at the same time, the turned-on resistance thereof can also be prevented effectively from increasing as well. Lattice defects are distributed at a high concentration in a defect region an area in close proximity to the boundary surface between an n drift region and a p+ substrate. The half-value width of the distribution is set at a value which is large enough for the defect region to include a non-depletion region in the n drift region. However, the defect region is not spread to cover a diffusion layer. In this way, the turning-off time of the semiconductor device can be reduced considerably without being accompanied by an increase in turned-on resistance thereof. In addition, by employing an absorber with an uneven surface, the distribution of lattice defects can be obtained by carrying out radiation of ions at only one time.Type: ApplicationFiled: January 2, 2001Publication date: August 9, 2001Applicant: Toyota Jidosha Kabushiki KaishaInventor: Tomoyoshi Kushida