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).
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Patent number: 9768246Abstract: 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: GrantFiled: January 28, 2016Date of Patent: September 19, 2017Assignee: FUJI ELECTRIC CO., LTD.Inventors: Takashi Yoshimura, Masayuki Miyazaki, Hiroshi Takishita, Hidenao Kuribayashi
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Patent number: 9722016Abstract: Proton irradiation is performed a plurality of times from rear surface of an n-type semiconductor substrate, which is an n? drift layer, forming an n-type FS layer having lower resistance than the n-type semiconductor substrate in the rear surface of the n? drift layer. When the proton irradiation is performed a plurality of times, the next proton irradiation is performed to as to compensate for a reduction in mobility due to disorder which remains after the previous proton irradiation. In this case, the second or subsequent proton irradiation is performed at the position of the disorder which is formed by the previous proton irradiation. In this way, even after proton irradiation and a heat treatment, the disorder is reduced and it is possible to prevent deterioration of characteristics, such as increase in leakage current. It is possible to form an n-type FS layer including a high-concentration hydrogen-related donor layer.Type: GrantFiled: May 17, 2016Date of Patent: August 1, 2017Assignee: FUJI ELECTRIC CO., LTD.Inventors: Hiroshi Takishita, Takashi Yoshimura, Masayuki Miyazaki, Hidenao Kuribayashi
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Publication number: 20170025520Abstract: A method of producing a semiconductor device is disclosed in which, after proton implantation is performed, a hydrogen-induced donor is formed by a furnace annealing process to form an n-type field stop layer. A disorder generated in a proton passage region is reduced by a laser annealing process to form an n-type disorder reduction region. As such, the n-type field stop layer and the n-type disorder reduction region are formed by the proton implantation. Therefore, it is possible to provide a stable and inexpensive semiconductor device which has low conduction resistance and can improve electrical characteristics, such as a leakage current, and a method for producing the semiconductor device.Type: ApplicationFiled: October 7, 2016Publication date: January 26, 2017Inventors: Masayuki MIYAZAKI, Takashi YOSHIMURA, Hiroshi TAKISHITA, Hidenao KURIBAYASHI
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Patent number: 9520475Abstract: A method of producing a seminconductor device is disclosed in which, after proton implantation is performed, a hydrogen-induced donor is formed by a furnace annealing process to form an n-type field stop layer. A disorder generated in a proton passage region is reduced by a laser annealing process to form an n-type disorder reduction region. As such, the n-type field stop layer and the n-type disorder reduction region are formed by the proton implantation. Therefore, it is possible to provide a stable and inexpensive semiconductor device which has low conduction resistance and can improve electrical characteristics, such as a leakage current, and a method for producing the semiconductor device.Type: GrantFiled: June 11, 2014Date of Patent: December 13, 2016Assignee: FUJI ELECTRIC CO., LTD.Inventors: Masayuki Miyazaki, Takashi Yoshimura, Hiroshi Takishita, Hidenao Kuribayashi
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Patent number: 9466689Abstract: A semiconductor device includes an input electrode provided on a front surface of a semiconductor substrate of a first conductivity type and an output electrode provided on a rear surface of the semiconductor substrate. The device has reduced deterioration of electrical characteristics when manufactured by a method including introducing impurities into the rear surface of the semiconductor substrate; activating the impurities using a first annealing process to form a first semiconductor layer, which is a contact portion in contact with the output electrode, in a surface layer of the rear surface; radiating protons to the rear surface; and activating the protons radiated using a second annealing process to form a second semiconductor layer of the first conductivity type, which has a higher impurity concentration than the semiconductor substrate, in a region that is deeper than the first semiconductor layer from the rear surface of the semiconductor substrate.Type: GrantFiled: March 29, 2013Date of Patent: October 11, 2016Assignee: FUJI ELECTRIC CO., LTD.Inventors: Masayuki Miyazaki, Takashi Yoshimura, Hiroshi Takishita, Hidenao Kuribayashi
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Publication number: 20160284796Abstract: A p+ collector layer is provided in a rear surface of a semiconductor substrate which will be an n? drift layer and an n+ field stop layer is provided in a region which is deeper than the p+ collector layer formed on the rear surface side. A front surface element structure is formed on the front surface of the semiconductor substrate and then protons are radiated to the rear surface of the semiconductor substrate at an acceleration voltage corresponding to the depth at which the n+ field stop layer is formed. A first annealing process is performed at an annealing temperature corresponding to the proton irradiation to change the protons into donors, thereby forming a field stop layer. Then, annealing is performed using annealing conditions suitable for the conditions of a plurality of proton irradiation processes to recover each crystal defect formed by each proton irradiation process.Type: ApplicationFiled: June 3, 2016Publication date: September 29, 2016Applicant: FUJI ELECTRIC CO., LTD.Inventors: Masayuki MIYAZAKI, Takashi YOSHIMURA, Hiroshi TAKISHITA, Hidenao KURIBAYASHI
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Publication number: 20160276446Abstract: 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: ApplicationFiled: June 1, 2016Publication date: September 22, 2016Inventors: Hiroki WAKIMOTO, Hiroshi TAKISHITA, Takashi YOSHIMURA, Takahiro TAMURA, Yuichi ONOZAWA
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Publication number: 20160268366Abstract: Proton irradiation is performed a plurality of times from rear surface of an n-type semiconductor substrate, which is an n? drift layer, forming an n-type FS layer having lower resistance than the n-type semiconductor substrate in the rear surface of the n? drift layer. When the proton irradiation is performed a plurality of times, the next proton irradiation is performed to as to compensate for a reduction in mobility due to disorder which remains after the previous proton irradiation. In this case, the second or subsequent proton irradiation is performed at the position of the disorder which is formed by the previous proton irradiation. In this way, even after proton irradiation and a heat treatment, the disorder is reduced and it is possible to prevent deterioration of characteristics, such as increase in leakage current. It is possible to form an n-type FS layer including a high-concentration hydrogen-related donor layer.Type: ApplicationFiled: May 17, 2016Publication date: September 15, 2016Inventors: Hiroshi TAKISHITA, Takashi YOSHIMURA, Masayuki MIYAZAKI, Hidenao KURIBAYASHI
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Patent number: 9385211Abstract: A p+ collector layer is provided in a rear surface of a semiconductor substrate which will be an n? drift layer and an n+ field stop layer is provided in a region which is deeper than the p+ collector layer formed on the rear surface side. A front surface element structure is formed on the front surface of the semiconductor substrate and then protons are radiated to the rear surface of the semiconductor substrate at an acceleration voltage corresponding to the depth at which the n+ field stop layer is formed. A first annealing process is performed at an annealing temperature corresponding to the proton irradiation to change the protons into donors, thereby forming a field stop layer. Then, annealing is performed using annealing conditions suitable for the conditions of a plurality of proton irradiation processes to recover each crystal defect formed by each proton irradiation process.Type: GrantFiled: March 29, 2013Date of Patent: July 5, 2016Assignee: FUJI ELECTRIC CO., LTD.Inventors: Masayuki Miyazaki, Takashi Yoshimura, Hiroshi Takishita, Hidenao Kuribayashi
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Patent number: 9368577Abstract: Proton irradiation is performed a plurality of times from rear surface of an n-type semiconductor substrate, which is an n? drift layer, forming an n-type FS layer having lower resistance than the n-type semiconductor substrate in the rear surface of the n? drift layer. When the proton irradiation is performed a plurality of times, the next proton irradiation is performed to as to compensate for a reduction in mobility due to disorder which remains after the previous proton irradiation. In this case, the second or subsequent proton irradiation is performed at the position of the disorder which is formed by the previous proton irradiation. In this way, even after proton irradiation and a heat treatment, the disorder is reduced and it is possible to prevent deterioration of characteristics, such as increase in leakage current. It is possible to form an n-type FS layer including a high-concentration hydrogen-related donor layer.Type: GrantFiled: May 13, 2014Date of Patent: June 14, 2016Assignee: FUJI ELECTRIC CO., LTD.Inventors: Hiroshi Takishita, Takashi Yoshimura, Masayuki Miyazaki, Hidenao Kuribayashi
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Publication number: 20160163786Abstract: 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: ApplicationFiled: January 28, 2016Publication date: June 9, 2016Inventors: Takashi YOSHIMURA, Masayuki MIYAZAKI, Hiroshi TAKISHITA, Hidenao KURIBAYASHI
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Patent number: 9276071Abstract: 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: GrantFiled: May 13, 2014Date of Patent: March 1, 2016Assignee: FUJI ELECTRIC CO., LTD.Inventors: Takashi Yoshimura, Masayuki Miyazaki, Hiroshi Takishita, Hidenao Kuribayashi
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Publication number: 20150364613Abstract: Provided is a semiconductor device and a method for forming the same. The device has a substrate including one and another surfaces. A first semiconductor region of a first conductivity type is formed in the substrate. A second conductivity type, second semiconductor region is provided in a first surface layer, that includes the one surface, of the substrate. A first electrode is in contact with the second semiconductor region to form a junction therebetween. A first conductivity type, third semiconductor region is provided in a second surface layer, that includes the another surface, of the substrate. The third semiconductor region has a higher impurity concentration than the first semiconductor region. A fourth semiconductor region of the second conductivity type is provided in the first semiconductor region at a location deeper than the third semiconductor region from the another surface. A second electrode is in contact with the third semiconductor region.Type: ApplicationFiled: August 7, 2015Publication date: December 17, 2015Applicant: FUJI ELECTRIC CO., LTD.Inventors: Yuichi ONOZAWA, Takashi YOSHIMURA, Hiroshi TAKISHITA
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Publication number: 20150311279Abstract: 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: ApplicationFiled: July 7, 2015Publication date: October 29, 2015Applicant: FUJI ELECTRIC CO., LTD.Inventors: Yuichi ONOZAWA, Hiroshi TAKISHITA, Takashi YOSHIMURA
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Publication number: 20150024556Abstract: A semiconductor device includes an input electrode provided on a front surface of a semiconductor substrate of a first conductivity type and an output electrode provided on a rear surface of the semiconductor substrate. The device has reduced deterioration of electrical characteristics when manufactured by a method including introducing impurities into the rear surface of the semiconductor substrate; activating the impurities using a first annealing process to form a first semiconductor layer, which is a contact portion in contact with the output electrode, in a surface layer of the rear surface; radiating protons to the rear surface; and activating the protons radiated using a second annealing process to form a second semiconductor layer of the first conductivity type, which has a higher impurity concentration than the semiconductor substrate, in a region that is deeper than the first semiconductor layer from the rear surface of the semiconductor substrate.Type: ApplicationFiled: March 29, 2013Publication date: January 22, 2015Applicant: FUJI ELECTRIC CO., LTD.Inventors: Masayuki Miyazaki, Takashi Yoshimura, Hiroshi Takishita, Hidenao Kuribayashi
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Publication number: 20140374793Abstract: A p+ collector layer is provided in a rear surface of a semiconductor substrate which will be an n? drift layer and an n+ field stop layer is provided in a region which is deeper than the p+ collector layer formed on the rear surface side. A front surface element structure is formed on the front surface of the semiconductor substrate and then protons are radiated to the rear surface of the semiconductor substrate at an acceleration voltage corresponding to the depth at which the n+ field stop layer is formed. A first annealing process is performed at an annealing temperature corresponding to the proton irradiation to change the protons into donors, thereby forming a field stop layer. Then, annealing is performed using annealing conditions suitable for the conditions of a plurality of proton irradiation processes to recover each crystal defect formed by each proton irradiation process.Type: ApplicationFiled: March 29, 2013Publication date: December 25, 2014Applicant: FUJI ELECTRIC CO., LTD.Inventors: Masayuki Miyazaki, Takashi Yoshimura, Hiroshi Takishita, Hidenao Kuribayashi
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Publication number: 20140291723Abstract: A method of producing a seminconductor device is disclosed in which, after proton implantation is performed, a hydrogen-induced donor is formed by a furnace annealing process to form an n-type field stop layer. A disorder generated in a proton passage region is reduced by a laser annealing process to form an n-type disorder reduction region. As such, the n-type field stop layer and the n-type disorder reduction region are formed by the proton implantation. Therefore, it is possible to provide a stable and inexpensive semiconductor device which has low conduction resistance and can improve electrical characteristics, such as a leakage current, and a method for producing the semiconductor device.Type: ApplicationFiled: June 11, 2014Publication date: October 2, 2014Inventors: Masayuki MIYAZAKI, Takashi YOSHIMURA, Hiroshi TAKISHITA, Hidenao KURIBAYASHI
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Publication number: 20140246750Abstract: Proton irradiation is performed a plurality of times from rear surface of an n-type semiconductor substrate, which is an n? drift layer, forming an n-type FS layer having lower resistance than the n-type semiconductor substrate in the rear surface of the n? drift layer. When the proton irradiation is performed a plurality of times, the next proton irradiation is performed to as to compensate for a reduction in mobility due to disorder which remains after the previous proton irradiation. In this case, the second or subsequent proton irradiation is performed at the position of the disorder which is formed by the previous proton irradiation. In this way, even after proton irradiation and a heat treatment, the disorder is reduced and it is possible to prevent deterioration of characteristics, such as increase in leakage current. It is possible to form an n-type FS layer including a high-concentration hydrogen-related donor layer.Type: ApplicationFiled: May 13, 2014Publication date: September 4, 2014Applicant: FUJI ELECTRIC CO., LTD.Inventors: Hiroshi TAKISHITA, Takashi YOSHIMURA, Masayuki MIYAZAKI, Hidenao KURIBAYASHI
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Publication number: 20140246755Abstract: 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: ApplicationFiled: May 13, 2014Publication date: September 4, 2014Applicant: FUJI ELECTRIC CO., LTD.Inventors: Takashi YOSHIMURA, Masayuki MIYAZAKI, Hiroshi TAKISHITA, Hidenao KURIBAYASHI