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).

  • Patent number: 10326025
    Abstract: To provide a semiconductor device including a thin film transistor having excellent electric characteristics and high reliability and a manufacturing method of the semiconductor device with high mass productivity. The summary is that an inverted-staggered (bottom-gate) thin film transistor is included in which an oxide semiconductor film containing In, Ga, and Zn is used as a semiconductor layer, a channel protective layer is provided in a region that overlaps a channel formation region of the semiconductor layer, and a buffer layer is provided between the semiconductor layer and source and drain electrodes. An ohmic contact is formed by intentionally providing the buffer layer having a higher carrier concentration than the semiconductor layer between the semiconductor layer and the source and drain electrodes.
    Type: Grant
    Filed: December 11, 2014
    Date of Patent: June 18, 2019
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Hidekazu Miyairi, Kengo Akimoto, Kojiro Shiraishi
  • Publication number: 20190172847
    Abstract: A protective circuit includes a non-linear element, which includes a gate electrode, a gate insulating layer covering the gate electrode, a pair of first and second wiring layers whose end portions overlap with the gate electrode over the gate insulating layer and in which a second oxide semiconductor layer and a conductive layer are stacked, and a first oxide semiconductor layer which overlaps with at least the gate electrode and which is in contact with the gate insulating layer, side face portions and part of top face portions of the conductive layer and side face portions of the second oxide semiconductor layer in the first wiring layer and the second wiring layer. Over the gate insulating layer, oxide semiconductor layers with different properties are bonded to each other, whereby stable operation can be performed as compared with Schottky junction. Thus, the junction leakage can be decreased and the characteristics of the non-linear element can be improved.
    Type: Application
    Filed: January 29, 2019
    Publication date: June 6, 2019
    Inventors: Shunpei YAMAZAKI, Kengo AKIMOTO, Shigeki KOMORI, Hideki UOCHI, Tomoya FUTAMURA, Takahiro KASAHARA
  • Patent number: 10304962
    Abstract: An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.
    Type: Grant
    Filed: August 3, 2015
    Date of Patent: May 28, 2019
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Kengo Akimoto, Tatsuya Honda, Norihito Sone
  • Publication number: 20190157461
    Abstract: An embodiment is to include an inverted staggered (bottom gate structure) thin film transistor in which an oxide semiconductor film containing In, Ga, and Zn is used as a semiconductor layer and a buffer layer is provided between the semiconductor layer and a source and drain electrode layers. The buffer layer having higher carrier concentration than the semiconductor layer is provided intentionally between the source and drain electrode layers and the semiconductor layer, whereby an ohmic contact is formed.
    Type: Application
    Filed: December 27, 2018
    Publication date: May 23, 2019
    Inventors: Shunpei YAMAZAKI, Hidekazu MIYAIRI, Akiharu MIYANAGA, Kengo AKIMOTO, Kojiro SHIRAISHI
  • Patent number: 10269978
    Abstract: An object is to improve field effect mobility of a thin film transistor using an oxide semiconductor. Another object is to suppress increase in off current even in a thin film transistor with improved field effect mobility. In a thin film transistor using an oxide semiconductor layer, by forming a semiconductor layer having higher electrical conductivity and a smaller thickness than the oxide semiconductor layer between the oxide semiconductor layer and a gate insulating layer, field effect mobility of the thin film transistor can be improved, and increase in off current can be suppressed.
    Type: Grant
    Filed: March 2, 2018
    Date of Patent: April 23, 2019
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Kengo Akimoto, Toshinari Sasaki
  • Patent number: 10256349
    Abstract: 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: Grant
    Filed: March 1, 2018
    Date of Patent: April 9, 2019
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Kengo Akimoto
  • Patent number: 10254607
    Abstract: 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: Grant
    Filed: March 8, 2018
    Date of Patent: April 9, 2019
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Kengo Akimoto, Shigeki Komori, Hideki Uochi, Tomoya Futamura, Takahiro Kasahara
  • Publication number: 20190088793
    Abstract: 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: Application
    Filed: November 15, 2018
    Publication date: March 21, 2019
    Inventors: Hajime KIMURA, Kengo AKIMOTO, Masashi TSUBUKU, Toshinari SASAKI
  • Patent number: 10236303
    Abstract: A protective circuit includes a non-linear element, which includes a gate electrode, a gate insulating layer covering the gate electrode, a pair of first and second wiring layers whose end portions overlap with the gate electrode over the gate insulating layer and in which a second oxide semiconductor layer and a conductive layer are stacked, and a first oxide semiconductor layer which overlaps with at least the gate electrode and which is in contact with the gate insulating layer, side face portions and part of top face portions of the conductive layer and side face portions of the second oxide semiconductor layer in the first wiring layer and the second wiring layer. Over the gate insulating layer, oxide semiconductor layers with different properties are bonded to each other, whereby stable operation can be performed as compared with Schottky junction. Thus, the junction leakage can be decreased and the characteristics of the non-linear element can be improved.
    Type: Grant
    Filed: May 29, 2014
    Date of Patent: March 19, 2019
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Kengo Akimoto, Shigeki Komori, Hideki Uochi, Tomoya Futamura, Takahiro Kasahara
  • Publication number: 20190081031
    Abstract: A protective circuit includes a non-linear element which includes a gate electrode, a gate insulating layer covering the gate electrode, a first oxide semiconductor layer overlapping with the gate electrode over the gate insulating layer, a channel protective layer overlapping with a channel formation region of the first oxide semiconductor layer, and a pair of a first wiring layer and a second wiring layer whose end portions overlap with the gate electrode over the channel protective layer and in which a conductive layer and a second oxide semiconductor layer are stacked. Over the gate insulating layer, oxide semiconductor layers with different properties are bonded to each other, whereby stable operation can be performed as compared with Schottky junction. Thus, the junction leakage can be reduced and the characteristics of the non-linear element can be improved.
    Type: Application
    Filed: November 13, 2018
    Publication date: March 14, 2019
    Inventors: Shunpei YAMAZAKI, Kengo AKIMOTO, Shigeki KOMORI, Hideki UOCHI, Tomoya FUTAMURA, Takahiro KASAHARA
  • Patent number: 10229904
    Abstract: A protective circuit includes a non-linear element which includes a gate electrode, a gate insulating layer covering the gate electrode, a first oxide semiconductor layer overlapping with the gate electrode over the gate insulating layer, a channel protective layer overlapping with a channel formation region of the first oxide semiconductor layer, and a pair of a first wiring layer and a second wiring layer whose end portions overlap with the gate electrode over the channel protective layer and in which a conductive layer and a second oxide semiconductor layer are stacked. Over the gate insulating layer, oxide semiconductor layers with different properties are bonded to each other, whereby stable operation can be performed as compared with Schottky junction. Thus, the junction leakage can be reduced and the characteristics of the non-linear element can be improved.
    Type: Grant
    Filed: April 30, 2015
    Date of Patent: March 12, 2019
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Kengo Akimoto, Shigeki Komori, Hideki Uochi, Tomoya Futamura, Takahiro Kasahara
  • Publication number: 20190074361
    Abstract: 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: Application
    Filed: November 5, 2018
    Publication date: March 7, 2019
    Inventors: Shunpei YAMAZAKI, Kengo AKIMOTO, Daisuke KAWAE
  • Publication number: 20190051759
    Abstract: An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.
    Type: Application
    Filed: October 17, 2018
    Publication date: February 14, 2019
    Inventors: Kengo AKIMOTO, Tatsuya HONDA, Norihito SONE
  • Patent number: 10205030
    Abstract: 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: Grant
    Filed: October 3, 2017
    Date of Patent: February 12, 2019
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hidekazu Miyairi, Kengo Akimoto, Yasuo Nakamura
  • Patent number: 10201514
    Abstract: There are provided microorganisms having a property of producing a lipid containing unsaturated fatty acids as constituent fatty acids and extracellularly secreting the produced lipid encapsulated in lipid particles, methods of screening said microorganisms, as well as methods of efficiently producing a fatty acid-containing lipid using said microorganisms. Furthermore, there are provided lipid particles encapsulating a lipid containing unsaturated fatty acids, and foods, cosmetics, and animal feeds comprising said lipid particles added thereto. Artificially treated microorganisms or microorganisms collected from nature are grown on a solid medium, and microbial strains that form lipid particles at the periphery of the colonies and/or microbial strains that, when cultured in a transparent liquid medium, make the culture liquid cloudy are selected.
    Type: Grant
    Filed: March 2, 2016
    Date of Patent: February 12, 2019
    Assignee: SUNTORY HOLDINGS LIMITED
    Inventors: Kengo Akimoto, Hiroshi Kawashima, Sakayu Shimizu
  • Publication number: 20190027640
    Abstract: 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: Application
    Filed: September 25, 2018
    Publication date: January 24, 2019
    Inventors: Shunpei YAMAZAKI, Kengo AKIMOTO, Shigeki KOMORI, Hideki UOCHI
  • Patent number: 10181545
    Abstract: 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: Grant
    Filed: December 5, 2012
    Date of Patent: January 15, 2019
    Assignee: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.
    Inventors: Shunpei Yamazaki, Kengo Akimoto, Shigeki Komori, Hideki Uochi
  • Patent number: 10176748
    Abstract: A novel information processing device that is highly convenient is provided. The information processing device includes a selection circuit having a function of supplying image data to a reflective display element, a light-emitting element, or both of them on the basis of input position coordinate data, sensing data about the illuminance of the usage environment, and the image data. An icon with high selection frequency is displayed by both the reflective display element and the light-emitting element on the basis of icon coordinate data and the input position coordinate data, so that the icon can be displayed brightly with improved visibility.
    Type: Grant
    Filed: January 26, 2017
    Date of Patent: January 8, 2019
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Kengo Akimoto, Isamu Shigemori
  • Patent number: 10158005
    Abstract: An object is to prevent an impurity such as moisture and oxygen from being mixed into an oxide semiconductor and suppress variation in semiconductor characteristics of a semiconductor device in which an oxide semiconductor is used. Another object is to provide a semiconductor device with high reliability. A gate insulating film provided over a substrate having an insulating surface, a source and a drain electrode which are provided over the gate insulating film, a first oxide semiconductor layer provided over the source electrode and the drain electrode, and a source and a drain region which are provided between the source electrode and the drain electrode and the first oxide semiconductor layer are provided. A barrier film is provided in contact with the first oxide semiconductor layer.
    Type: Grant
    Filed: December 3, 2013
    Date of Patent: December 18, 2018
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Kengo Akimoto, Shunpei Yamazaki
  • Patent number: 10153346
    Abstract: 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: Grant
    Filed: March 24, 2016
    Date of Patent: December 11, 2018
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Kengo Akimoto, Yusuke Nonaka, Hiroshi Kanemura