Patents by Inventor Yuhei Sato
Yuhei Sato 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: 9831326Abstract: A method for manufacturing a semiconductor device includes the steps of forming a first insulating film over a first gate electrode over a substrate while heated at a temperature higher than or equal to 450° C. and lower than the strain point of the substrate, forming a first oxide semiconductor film over the first insulating film, adding oxygen to the first oxide semiconductor film and then forming a second oxide semiconductor film over the first oxide semiconductor film, and performing heat treatment so that part of oxygen contained in the first oxide semiconductor film is transferred to the second oxide semiconductor film.Type: GrantFiled: November 14, 2016Date of Patent: November 28, 2017Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Tetsuhiro Tanaka, Masayuki Sakakura, Ryo Tokumaru, Yasumasa Yamane, Yuhei Sato
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Patent number: 9812544Abstract: To manufacture a transistor whose threshold voltage is controlled without using a backgate electrode, a circuit for controlling the threshold voltage, and an impurity introduction method. To manufacture a semiconductor device having favorable electrical characteristics, high reliability, and low power consumption using the transistor. A gate electrode including a tungsten oxide film whose composition is controlled is used. The composition or the like is adjusted by a film formation method of the tungsten oxide film, whereby the work function can be controlled. By using the tungsten oxide film whose work function is controlled as part of the gate electrode, the threshold of the transistor can be controlled. Using the transistor whose threshold voltage is controlled, a semiconductor device having favorable electrical characteristics, high reliability, and low power consumption can be manufactured.Type: GrantFiled: November 9, 2015Date of Patent: November 7, 2017Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Yuta Endo, Toshinari Sasaki, Kosei Noda, Hitomi Sato, Yuhei Sato
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Publication number: 20170294542Abstract: A transistor with stable electrical characteristics is provided. The transistor includes a first insulator over a substrate; first to third oxide insulators over the first insulator; a second insulator over the third oxide insulator; a first conductor over the second insulator; and a third insulator over the first conductor. An energy level of a conduction band minimum of each of the first and second oxide insulators is closer to a vacuum level than that of the oxide semiconductor is. An energy level of a conduction band minimum of the third oxide insulator is closer to the vacuum level than that of the second oxide insulator is. The first insulator contains oxygen. The number of oxygen molecules released from the first insulator measured by thermal desorption spectroscopy is greater than or equal to 1E14 molecules/cm2 and less than or equal to 1E16 molecules/cm2.Type: ApplicationFiled: June 26, 2017Publication date: October 12, 2017Applicant: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei YAMAZAKI, Tetsuhiro TANAKA, Akihisa SHIMOMURA, Yasumasa YAMANE, Ryo TOKUMARU, Yuhei SATO, Kazuhiro TSUTSUI
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Patent number: 9722056Abstract: A change in electrical characteristics is suppressed and reliability in a semiconductor device using a transistor including an oxide semiconductor is improved. Oxygen is introduced into a surface of an insulating film, and then, an oxide semiconductor, a layer which is capable of blocking oxygen, a gate insulating film, and other films which composes a transistor are formed. For at least one of the first gate insulating film and the insulating film, three signals in Electron Spin Resonance Measurement are each observed in a certain range of g-factor. Reducing the sum of the spin densities of the signals will improve reliability of the semiconductor device.Type: GrantFiled: September 27, 2016Date of Patent: August 1, 2017Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Akihisa Shimomura, Yasumasa Yamane, Yuhei Sato, Tetsuhiro Tanaka, Masashi Tsubuku, Toshihiko Takeuchi, Ryo Tokumaru, Mitsuhiro Ichijo, Satoshi Toriumi, Takashi Ohtsuki, Toshiya Endo
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Patent number: 9698277Abstract: A transistor with stable electrical characteristics is provided. The transistor includes a first insulator over a substrate; first to third oxide insulators over the first insulator; a second insulator over the third oxide insulator; a first conductor over the second insulator; and a third insulator over the first conductor. An energy level of a conduction band minimum of each of the first and second oxide insulators is closer to a vacuum level than that of the oxide semiconductor is. An energy level of a conduction band minimum of the third oxide insulator is closer to the vacuum level than that of the second oxide insulator is. The first insulator contains oxygen. The number of oxygen molecules released from the first insulator measured by thermal desorption spectroscopy is greater than or equal to 1E14 molecules/cm2 and less than or equal to 1E16 molecules/cm2.Type: GrantFiled: December 9, 2015Date of Patent: July 4, 2017Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Tetsuhiro Tanaka, Akihisa Shimomura, Yasumasa Yamane, Ryo Tokumaru, Yuhei Sato, Kazuhiro Tsutsui
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Patent number: 9673306Abstract: The amount of water and hydrogen contained in an oxide semiconductor film is reduced, and oxygen is supplied sufficiently from a base film to the oxide semiconductor film in order to reduce oxygen deficiencies. A stacked base film is formed, a first heat treatment is performed, an oxide semiconductor film is formed over and in contact with the stacked base film, and a second heat treatment is performed. In the stacked base film, a first base film and a second base film are stacked in this order. The first base film is an insulating oxide film from which oxygen is released by heating. The second base film is an insulating metal oxide film. An oxygen diffusion coefficient of the second base film is smaller than that of the first base film.Type: GrantFiled: December 26, 2014Date of Patent: June 6, 2017Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Yuki Imoto, Yuhei Sato
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Publication number: 20170141233Abstract: Favorable electrical characteristics are given to a semiconductor device. Furthermore, a semiconductor device having high reliability is provided. One embodiment of the present invention is an oxide semiconductor film having a plurality of electron diffraction patterns which are observed in such a manner that a surface where the oxide semiconductor film is formed is irradiated with an electron beam having a probe diameter whose half-width is 1 nm. The plurality of electron diffraction patterns include 50 or more electron diffraction patterns which are observed in different areas, the sum of the percentage of first electron diffraction patterns and the percentage of second electron diffraction patterns accounts for 100%, the first electron diffraction patterns account for 90% or more, the first electron diffraction pattern includes observed points which indicates that a c-axis is oriented in a direction substantially perpendicular to the surface where the oxide semiconductor film is formed.Type: ApplicationFiled: January 27, 2017Publication date: May 18, 2017Inventors: Akihisa SHIMOMURA, Yasumasa YAMANE, Yuhei SATO, Takahisa ISHIYAMA, Kenichi OKAZAKI, Chiho KAWANABE, Masashi OOTA, Noritaka ISHIHARA
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Patent number: 9653613Abstract: Provided is a transistor with stable electrical characteristics. Provided is a semiconductor device including an oxide semiconductor over a substrate, a first conductor in contact with a top surface of the oxide semiconductor, a second conductor in contact with the top surface of the oxide semiconductor, a first insulator over the first and second conductors and in contact with the top surface of the oxide semiconductor, a second insulator over the first insulator, a third conductor over the second insulator, and a third insulator over the third conductor. The third conductor overlaps with the first conductor with the first and second insulators positioned therebetween, and overlaps with the second conductor with the first and second insulators positioned therebetween. The first insulator contains oxygen. The second insulator transmits less oxygen than the first insulator. The third insulator transmits less oxygen than the first insulator.Type: GrantFiled: February 19, 2016Date of Patent: May 16, 2017Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Tetsuhiro Tanaka, Akihisa Shimomura, Ryo Tokumaru, Yasumasa Yamane, Yuhei Sato, Naoki Okuno, Motoki Nakashima
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Publication number: 20170125553Abstract: A method for manufacturing a semiconductor device includes the steps of forming a first insulating film over a first gate electrode over a substrate while heated at a temperature higher than or equal to 450° C. and lower than the strain point of the substrate, forming a first oxide semiconductor film over the first insulating film, adding oxygen to the first oxide semiconductor film and then forming a second oxide semiconductor film over the first oxide semiconductor film, and performing heat treatment so that part of oxygen contained in the first oxide semiconductor film is transferred to the second oxide semiconductor film.Type: ApplicationFiled: November 14, 2016Publication date: May 4, 2017Inventors: Shunpei YAMAZAKI, Tetsuhiro TANAKA, Masayuki SAKAKURA, Ryo TOKUMARU, Yasumasa YAMANE, Yuhei SATO
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Publication number: 20170117305Abstract: A semiconductor device using an oxide semiconductor is provided with stable electric characteristics to improve the reliability. In a manufacturing process of a transistor including an oxide semiconductor film, an oxide semiconductor film containing a crystal having a c-axis which is substantially perpendicular to a top surface thereof (also called a first crystalline oxide semiconductor film) is formed; oxygen is added to the oxide semiconductor film to amorphize at least part of the oxide semiconductor film, so that an amorphous oxide semiconductor film containing an excess of oxygen is formed; an aluminum oxide film is formed over the amorphous oxide semiconductor film; and heat treatment is performed thereon to crystallize at least part of the amorphous oxide semiconductor film, so that an oxide semiconductor film containing a crystal having a c-axis which is substantially perpendicular to a top surface thereof (also called a second crystalline oxide semiconductor film) is formed.Type: ApplicationFiled: January 5, 2017Publication date: April 27, 2017Inventors: Junichi KOEZUKA, Naoto YAMADE, Yuhei SATO, Yutaka OKAZAKI, Shunpei YAMAZAKI
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Publication number: 20170033230Abstract: To provide a transistor with stable electrical characteristics, a transistor with a low off-state current, a transistor with a high on-state current, a semiconductor device including the transistor, or a durable semiconductor device. The semiconductor device includes a first transistor using silicon, an aluminum oxide film over the first transistor, and a second transistor using an oxide semiconductor over the aluminum oxide film. The oxide semiconductor has a lower hydrogen concentration than silicon.Type: ApplicationFiled: October 13, 2016Publication date: February 2, 2017Inventors: Shunpei YAMAZAKI, Tetsuhiro TANAKA, Hideomi SUZAWA, Yasumasa YAMANE, Yuhei SATO, Sachiaki TEZUKA
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Patent number: 9559174Abstract: Favorable electrical characteristics are given to a semiconductor device. Furthermore, a semiconductor device having high reliability is provided. One embodiment of the present invention is an oxide semiconductor film having a plurality of electron diffraction patterns which are observed in such a manner that a surface where the oxide semiconductor film is formed is irradiated with an electron beam having a probe diameter whose half-width is 1 nm. The plurality of electron diffraction patterns include 50 or more electron diffraction patterns which are observed in different areas, the sum of the percentage of first electron diffraction patterns and the percentage of second electron diffraction patterns accounts for 100%, the first electron diffraction patterns account for 90% or more, the first electron diffraction pattern includes observed points which indicates that a c-axis is oriented in a direction substantially perpendicular to the surface where the oxide semiconductor film is formed.Type: GrantFiled: March 14, 2016Date of Patent: January 31, 2017Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Akihisa Shimomura, Yasumasa Yamane, Yuhei Sato, Takahisa Ishiyama, Kenichi Okazaki, Chiho Kawanabe, Masashi Oota, Noritaka Ishihara
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Publication number: 20170018631Abstract: A change in electrical characteristics is suppressed and reliability in a semiconductor device using a transistor including an oxide semiconductor is improved. The semiconductor device includes an oxide semiconductor film over an insulating surface, an antioxidant film over the insulating surface and the oxide semiconductor film, a pair of electrodes in contact with the antioxidant film, a gate insulating film over the pair of electrodes, and a gate electrode which is over the gate insulating film and overlaps with the oxide semiconductor film. In the antioxidant film, a width of a region overlapping with the pair of electrodes is longer than a width of a region not overlapping with the pair of electrodes.Type: ApplicationFiled: September 27, 2016Publication date: January 19, 2017Inventors: Shunpei YAMAZAKI, Akihisa SHIMOMURA, Yasumasa YAMANE, Yuhei SATO, Tetsuhiro TANAKA, Masashi TSUBUKU, Toshihiko TAKEUCHI, Ryo TOKUMARU, Mitsuhiro ICHIJO, Satoshi TORIUMI, Takashi OHTSUKI, Toshiya ENDO
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Publication number: 20170012138Abstract: A transistor having high field-effect mobility is provided. A transistor having stable electrical characteristics is provided. A transistor having small current in an off state (in a non-conductive state) is provided. A semiconductor device including such a transistor is provided. A first electrode is formed over a substrate, a first insulating layer is formed adjacent to a side surface of the first electrode, and a second insulating layer is formed to cover the first insulating layer and be in contact with at least part of a surface of the first electrode. The surface of the first electrode is formed of a conductive material that does not easily transmit an impurity element. The second insulating layer is formed of an insulating material that does not easily transmit an impurity element. An oxide semiconductor layer is formed over the first electrode with a third insulating layer provided therebetween.Type: ApplicationFiled: September 20, 2016Publication date: January 12, 2017Inventors: Hideomi SUZAWA, Tetsuhiro TANAKA, Yuhei SATO, Sachiaki TEZUKA, Shunpei YAMAZAKI
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Patent number: 9543145Abstract: A semiconductor device using an oxide semiconductor is provided with stable electric characteristics to improve the reliability. In a manufacturing process of a transistor including an oxide semiconductor film, an oxide semiconductor film containing a crystal having a c-axis which is substantially perpendicular to a top surface thereof (also called a first crystalline oxide semiconductor film) is formed; oxygen is added to the oxide semiconductor film to amorphize at least part of the oxide semiconductor film, so that an amorphous oxide semiconductor film containing an excess of oxygen is formed; an aluminum oxide film is formed over the amorphous oxide semiconductor film; and heat treatment is performed thereon to crystallize at least part of the amorphous oxide semiconductor film, so that an oxide semiconductor film containing a crystal having a c-axis which is substantially perpendicular to a top surface thereof (also called a second crystalline oxide semiconductor film) is formed.Type: GrantFiled: February 18, 2016Date of Patent: January 10, 2017Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Junichi Koezuka, Naoto Yamade, Yuhei Sato, Yutaka Okazaki, Shunpei Yamazaki
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Patent number: 9496411Abstract: A method for manufacturing a semiconductor device includes the steps of forming a first insulating film over a first gate electrode over a substrate while heated at a temperature higher than or equal to 450° C. and lower than the strain point of the substrate, forming a first oxide semiconductor film over the first insulating film, adding oxygen to the first oxide semiconductor film and then forming a second oxide semiconductor film over the first oxide semiconductor film, and performing heat treatment so that part of oxygen contained in the first oxide semiconductor film is transferred to the second oxide semiconductor film.Type: GrantFiled: May 22, 2015Date of Patent: November 15, 2016Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Tetsuhiro Tanaka, Masayuki Sakakura, Ryo Tokumaru, Yasumasa Yamane, Yuhei Sato
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Patent number: 9478664Abstract: A change in electrical characteristics is suppressed and reliability in a semiconductor device using a transistor including an oxide semiconductor is improved. The semiconductor device includes an oxide semiconductor film over an insulating surface, an antioxidant film over the insulating surface and the oxide semiconductor film, a pair of electrodes in contact with the antioxidant film, a gate insulating film over the pair of electrodes, and a gate electrode which is over the gate insulating film and overlaps with the oxide semiconductor film. In the antioxidant film, a width of a region overlapping with the pair of electrodes is longer than a width of a region not overlapping with the pair of electrodes.Type: GrantFiled: December 18, 2014Date of Patent: October 25, 2016Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Akihisa Shimomura, Yasumasa Yamane, Yuhei Sato, Tetsuhiro Tanaka, Masashi Tsubuku, Toshihiko Takeuchi, Ryo Tokumaru, Mitsuhiro Ichijo, Satoshi Toriumi, Takashi Ohtsuki, Toshiya Endo
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Patent number: 9472678Abstract: To provide a transistor with stable electrical characteristics, a transistor with a low off-state current, a transistor with a high on-state current, a semiconductor device including the transistor, or a durable semiconductor device. The semiconductor device includes a first transistor using silicon, an aluminum oxide film over the first transistor, and a second transistor using an oxide semiconductor over the aluminum oxide film. The oxide semiconductor has a lower hydrogen concentration than silicon.Type: GrantFiled: December 23, 2014Date of Patent: October 18, 2016Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Tetsuhiro Tanaka, Hideomi Suzawa, Yasumasa Yamane, Yuhei Sato, Sachiaki Tezuka
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Publication number: 20160284564Abstract: In a manufacturing process of a transistor including an oxide semiconductor film, oxygen doping treatment is performed on the oxide semiconductor film, and then heat treatment is performed on the oxide semiconductor film and an aluminum oxide film provided over the oxide semiconductor film. Consequently, an oxide semiconductor film which includes a region containing more oxygen than a stoichiometric composition is formed. The transistor formed using the oxide semiconductor film can have high reliability because the amount of change in the threshold voltage of the transistor by a bias-temperature stress test (BT test) is reduced.Type: ApplicationFiled: June 1, 2016Publication date: September 29, 2016Inventors: Shunpei YAMAZAKI, Yuhei SATO, Keiji SATO, Tetsunori MARUYAMA, Junichi KOEZUKA
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Patent number: 9455349Abstract: A transistor having high field-effect mobility is provided. A transistor having stable electrical characteristics is provided. A transistor having small current in an off state (in a non-conductive state) is provided. A semiconductor device including such a transistor is provided. A first electrode is formed over a substrate, a first insulating layer is formed adjacent to a side surface of the first electrode, and a second insulating layer is formed to cover the first insulating layer and be in contact with at least part of a surface of the first electrode. The surface of the first electrode is formed of a conductive material that does not easily transmit an impurity element. The second insulating layer is formed of an insulating material that does not easily transmit an impurity element. An oxide semiconductor layer is formed over the first electrode with a third insulating layer provided therebetween.Type: GrantFiled: October 20, 2014Date of Patent: September 27, 2016Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Hideomi Suzawa, Tetsuhiro Tanaka, Yuhei Sato, Sachiaki Tezuka, Shunpei Yamazaki