Patents by Inventor Kengo Akimoto
Kengo Akimoto 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: 9343584Abstract: An object is to provide a semiconductor device including an oxide semiconductor film, which has stable electrical characteristics and high reliability. A stack of first and second material films is formed by forming the first material film (a film having a hexagonal crystal structure) having a thickness of 1 nm to 10 nm over an insulating surface and forming the second material film having a hexagonal crystal structure (a crystalline oxide semiconductor film) using the first material film as a nucleus. As the first material film, a material film having a wurtzite crystal structure (e.g., gallium nitride or aluminum nitride) or a material film having a corundum crystal structure (?-Al2O3, ?-Ga2O3, In2O3, Ti2O3, V2O3, Cr2O3, or ?-Fe2O3) is used.Type: GrantFiled: August 6, 2015Date of Patent: May 17, 2016Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Yusuke Nonaka, Takayuki Inoue, Masashi Tsubuku, Kengo Akimoto, Akiharu Miyanaga
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Patent number: 9341722Abstract: An imaging device which is highly stable to irradiation with radiations such as X-rays and can inhibit a decrease in electrical characteristics is provided. The imaging device obtains an image using radiations such as X-rays and includes pixel circuits which are arranged in a matrix and which a scintillator overlaps. Each of the pixel circuits includes a switching transistor whose off-state current is extremely low and a light-receiving element. A shielding layer formed using a metal material and the like overlaps the transistor and the light-receiving element. With the structure, an imaging device which is highly stable to irradiation with radiations such as X-rays and can inhibit a decrease in electrical characteristics can be provided.Type: GrantFiled: February 24, 2014Date of Patent: May 17, 2016Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Kengo Akimoto, Hironobu Takahashi, Hiroshi Kanemura, Akiharu Miyanaga
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Patent number: 9343517Abstract: A display device includes a pixel portion in which a pixel electrode layer is arranged in a matrix, and an inverted staggered thin film transistor having a combination of at least two kinds of oxide semiconductor layers with different amounts of oxygen is provided corresponding to the pixel electrode layer. In the periphery of the pixel portion in this display device, a pad portion is provided to be electrically connected to a common electrode layer formed on a counter substrate through a conductive layer made of the same material as the pixel electrode layer. One objection of our invention to prevent a defect due to separation of a thin film in various kinds of display devices is realized, by providing a structure suitable for a pad portion provided in a display panel.Type: GrantFiled: February 3, 2011Date of Patent: May 17, 2016Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Kengo Akimoto, Shigeki Komori, Hideki Uochi, Rihito Wada, Yoko Chiba
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Patent number: 9331208Abstract: An oxide semiconductor film which has more stable electric conductivity is provided. The oxide semiconductor film comprises a crystalline region. The oxide semiconductor film has a first peak of electron diffraction intensity with a full width at half maximum of greater than or equal to 0.4 nm?1 and less than or equal to 0.7 nm?1 in a region where a magnitude of a scattering vector is greater than or equal to 3.3 nm?1 and less than or equal to 4.1 nm?1. The oxide semiconductor film has a second peak of electron diffraction intensity with a full width at half maximum of greater than or equal to 0.45 nm?1 and less than or equal to 1.4 nm?1 in a region where a magnitude of a scattering vector is greater than or equal to 5.5 nm?1 and less than or equal to 7.1 nm?1.Type: GrantFiled: March 2, 2015Date of Patent: May 3, 2016Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Masashi Tsubuku, Kengo Akimoto, Hiroki Ohara, Tatsuya Honda, Takatsugu Omata, Yusuke Nonaka, Masahiro Takahashi, Akiharu Miyanaga
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Patent number: 9331156Abstract: To manufacture a highly reliable semiconductor device by giving stable electric characteristics to a transistor. An oxide semiconductor film is deposited by a sputtering method with the use of a polycrystalline sputtering target. In that case, partial pressure of water in a deposition chamber before or in the deposition is set to be lower than or equal to 10?3 Pa, preferably lower than or equal to 10?4 Pa, more preferably lower than or equal to 10?5 Pa. Thus, a dense oxide semiconductor film is obtained. The density of the oxide semiconductor film is higher than 6.0 g/cm3 and lower than 6.375 g/cm3.Type: GrantFiled: December 11, 2012Date of Patent: May 3, 2016Assignee: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.Inventors: Shunpei Yamazaki, Kengo Akimoto, Yusuke Nonaka, Hiroshi Kanemura
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Patent number: 9331306Abstract: An organic optical device which can suppress deterioration due to moisture or an impurity is provided. An organic optical device includes a supporting body, a functional layer provided over the supporting body, and a light-emitting body containing an organic compound provided over the functional layer. The functional layer includes an insulating film containing gallium or aluminum, zinc, and oxygen. The supporting body and the functional layer each have a property of transmitting light with a wavelength of greater than or equal to 400 nm and less than or equal to 700 nm. By using the insulating film containing gallium or aluminum, zinc, and oxygen as a protective film, entry of moisture or an impurity into an organic compound or a metal material can be suppressed.Type: GrantFiled: November 22, 2011Date of Patent: May 3, 2016Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Hisao Ikeda, Kengo Akimoto
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Patent number: 9324874Abstract: A pixel portion and a driver circuit driving the pixel portion are formed over the same substrate. At least a part of the driver circuit is formed using an inverted staggered thin film transistor in which an oxide semiconductor layer is used and a channel protective layer is provided over the oxide semiconductor layer serving as a channel formation region which is overlapped with the gate electrode. The driver circuit as well as the pixel portion is provided over the same substrate to reduce manufacturing costs.Type: GrantFiled: September 28, 2009Date of Patent: April 26, 2016Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Kengo Akimoto, Atsushi Umezaki
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Publication number: 20160111282Abstract: It is an object to provide an oxide semiconductor which is suitable for use in a semiconductor device. Alternatively, it is another object to provide a semiconductor device using the oxide semiconductor. Provided is a semiconductor device including an In—Ga—Zn—O based oxide semiconductor layer in a channel formation region of a transistor. In the semiconductor device, the In—Ga—Zn—O based oxide semiconductor layer has a structure in which crystal grains represented by InGaO3(ZnO)m (m=1) are included in an amorphous structure represented by InGaO3(ZnO)m (m>0).Type: ApplicationFiled: December 17, 2015Publication date: April 21, 2016Inventors: Kengo AKIMOTO, Junichiro SAKATA, Takuya HIROHASHI, Masahiro TAKAHASHI, Hideyuki KISHIDA, Akiharu MIYANAGA
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Patent number: 9318617Abstract: It is an object to provide a highly reliable semiconductor device with good electrical characteristics and a display device including the semiconductor device as a switching element. In a transistor including an oxide semiconductor layer, a needle crystal group provided on at least one surface side of the oxide semiconductor layer grows in a c-axis direction perpendicular to the surface and includes an a-b plane parallel to the surface, and a portion except for the needle crystal group is an amorphous region or a region in which amorphousness and microcrystals are mixed. Accordingly, a highly reliable semiconductor device with good electrical characteristics can be formed.Type: GrantFiled: December 18, 2014Date of Patent: April 19, 2016Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Masayuki Sakakura, Ryosuke Watanabe, Junichiro Sakata, Kengo Akimoto, Akiharu Miyanaga, Takuya Hirohashi, Hideyuki Kishida
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Patent number: 9293545Abstract: A structure by which electric-field concentration which might occur between a source electrode and a drain electrode in a bottom-gate thin film transistor is relaxed and deterioration of the switching characteristics is suppressed, and a manufacturing method thereof. A bottom-gate thin film transistor in which an oxide semiconductor layer is provided over a source and drain electrodes is manufactured, and angle ?1 of the side surface of the source electrode which is in contact with the oxide semiconductor layer and angle ?2 of the side surface of the drain electrode which is in contact with the oxide semiconductor layer are each set to be greater than or equal to 20° and less than 90°, so that the distance from the top edge to the bottom edge in the side surface of each electrode is increased.Type: GrantFiled: August 5, 2014Date of Patent: March 22, 2016Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Kengo Akimoto, Daisuke Kawae
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Publication number: 20160079438Abstract: To provide a method by which a semiconductor device including a thin film transistor with excellent electric characteristics and high reliability is manufactured with a small number of steps. After a channel protective layer is formed over an oxide semiconductor film containing In, Ga, and Zn, a film having n-type conductivity and a conductive film are formed, and a resist mask is formed over the conductive film. The conductive film, the film having n-type conductivity, and the oxide semiconductor film containing In, Ga, and Zn are etched using the channel protective layer and gate insulating films as etching stoppers with the resist mask, so that source and drain electrode layers, a buffer layer, and a semiconductor layer are formed.Type: ApplicationFiled: November 19, 2015Publication date: March 17, 2016Inventors: Hidekazu MIYAIRI, Kengo AKIMOTO, Yasuo NAKAMURA
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Publication number: 20160079439Abstract: An object is to provide favorable interface characteristics of a thin film transistor including an oxide semiconductor layer without mixing of an impurity such as moisture. Another object is to provide a semiconductor device including a thin film transistor having excellent electric characteristics and high reliability, and a method by which a semiconductor device can be manufactured with high productivity. A main point is to perform oxygen radical treatment on a surface of a gate insulating layer. Accordingly, there is a peak of the oxygen concentration at an interface between the gate insulating layer and a semiconductor layer, and the oxygen concentration of the gate insulating layer has a concentration gradient. The oxygen concentration is increased toward the interface between the gate insulating layer and the semiconductor layer.Type: ApplicationFiled: November 20, 2015Publication date: March 17, 2016Inventors: Shunpei YAMAZAKI, Kengo AKIMOTO
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Patent number: 9257082Abstract: A display device including a pixel having a memory. The pixel includes at least a display element, a capacitor, an inverter, and a switch. The switch is controlled with a signal held in the capacitor and a signal output from the inverter so that voltage is supplied to the display element. The inverter and the switch can be constituted by transistors with the same polarity. A semiconductor layer included in the pixel may be formed using a light-transmitting material. Moreover, a gate electrode, a drain electrode, and a capacitor electrode may be formed using a light-transmitting conductive layer. The pixel is formed using a light-transmitting material in such a manner, whereby the display device can be a transmissive display device while including a pixel having a memory.Type: GrantFiled: August 31, 2010Date of Patent: February 9, 2016Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Hajime Kimura, Kengo Akimoto, Masashi Tsubuku, Toshinari Sasaki
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Patent number: 9257594Abstract: An object is to provide a semiconductor device including a thin film transistor with excellent electrical characteristics and high reliability and a method for manufacturing the semiconductor device with high mass productivity. A main point is to form a low-resistance oxide semiconductor layer as a source or drain region after forming a drain or source electrode layer over a gate insulating layer and to form an oxide semiconductor film thereover as a semiconductor layer. It is preferable that an oxygen-excess oxide semiconductor layer be used as a semiconductor layer and an oxygen-deficient oxide semiconductor layer be used as a source region and a drain region.Type: GrantFiled: September 3, 2009Date of Patent: February 9, 2016Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Shunpei Yamazaki, Kengo Akimoto, Shigeki Komori, Hideki Uochi
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Patent number: 9252288Abstract: It is an object to provide an oxide semiconductor which is suitable for use in a semiconductor device. Alternatively, it is another object to provide a semiconductor device using the oxide semiconductor. Provided is a semiconductor device including an In—Ga—Zn—O based oxide semiconductor layer in a channel formation region of a transistor. In the semiconductor device, the In—Ga—Zn—O based oxide semiconductor layer has a structure in which crystal grains represented by InGaO3(ZnO)m (m=1) are included in an amorphous structure represented by InGaO3(ZnO)m (m>0).Type: GrantFiled: December 24, 2013Date of Patent: February 2, 2016Assignee: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.Inventors: Kengo Akimoto, Junichiro Sakata, Takuya Hirohashi, Masahiro Takahashi, Hideyuki Kishida, Akiharu Miyanaga
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Patent number: 9236456Abstract: To provide a method by which a semiconductor device including a thin film transistor with excellent electric characteristics and high reliability is manufactured with a small number of steps. After a channel protective layer is formed over an oxide semiconductor film containing In, Ga, and Zn, a film having n-type conductivity and a conductive film are formed, and a resist mask is formed over the conductive film. The conductive film, the film having n-type conductivity, and the oxide semiconductor film containing In, Ga, and Zn are etched using the channel protective layer and gate insulating films as etching stoppers with the resist mask, so that source and drain electrode layers, a buffer layer, and a semiconductor layer are formed.Type: GrantFiled: May 14, 2015Date of Patent: January 12, 2016Assignee: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.Inventors: Hidekazu Miyairi, Kengo Akimoto, Yasuo Nakamura
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Patent number: 9224839Abstract: To provide a method for manufacturing a thin film transistor in which contact resistance between an oxide semiconductor layer and source and drain electrode layers is small, the surfaces of the source and drain electrode layers are subjected to sputtering treatment with plasma and an oxide semiconductor layer containing In, Ga, and Zn is formed successively over the source and drain electrode layers without exposure of the source and drain electrode layers to air.Type: GrantFiled: August 14, 2014Date of Patent: December 29, 2015Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Kengo Akimoto, Masashi Tsubuku
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Patent number: 9219158Abstract: As a display device has a higher definition, the number of pixels, gate lines, and signal lines are increased. When the number of the gate lines and the signal lines are increased, there occurs a problem that it is difficult to mount an IC chip including a driver circuit for driving the gate and signal lines by bonding or the like, whereby manufacturing cost is increased. A pixel portion and a driver circuit for driving the pixel portion are provided over the same substrate, and at least part of the driver circuit includes a thin film transistor using an oxide semiconductor interposed between gate electrodes provided above and below the oxide semiconductor. The pixel portion and the driver portion are provided over the same substrate, whereby manufacturing cost can be reduced.Type: GrantFiled: April 2, 2015Date of Patent: December 22, 2015Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Hidekazu Miyairi, Takeshi Osada, Kengo Akimoto, Shunpei Yamazaki
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Publication number: 20150364513Abstract: An imaging device with high imaging quality capable of being manufactured at low cost is provided. The imaging device includes a first transistor, a second transistor, a third transistor, a fourth transistor, a photodiode, and a capacitor. Each of the first to the fourth transistors includes a first gate electrode and a second gate electrode, and the second gate electrode of each of the first to the fourth transistors and one electrode of the capacitor are electrically connected to an anode electrode of the photodiode.Type: ApplicationFiled: June 5, 2015Publication date: December 17, 2015Inventors: Hironobu TAKAHASHI, Yukinori SHIMA, Kengo AKIMOTO, Junichi KOEZUKA, Naoto KUSUMOTO
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Publication number: 20150362806Abstract: In order to take advantage of the properties of a display device including an oxide semiconductor, a protective circuit and the like having appropriate structures and a small occupied area are necessary. The protective circuit is formed using a non-linear element which includes a gate insulating film covering a gate electrode; a first oxide semiconductor layer over the gate insulating film; a channel protective layer covering a region which overlaps with a channel formation region of the first oxide semiconductor layer; and a first wiring layer and a second wiring layer each of which is formed by stacking a conductive layer and a second oxide semiconductor layer and over the first oxide semiconductor layer. The gate electrode is connected to a scan line or a signal line, the first wiring layer or the second wiring layer is directly connected to the gate electrode.Type: ApplicationFiled: August 27, 2015Publication date: December 17, 2015Inventors: Shunpei YAMAZAKI, Kengo AKIMOTO, Shigeki KOMORI, Hideki UOCHI, Tomoya FUTAMURA, Takahiro KASAHARA
