Patents by Inventor Hideto Tamaso

Hideto Tamaso 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: 9129804
    Abstract: The present invention provides a silicon carbide semiconductor device having an ohmic electrode improved in adhesion of a wire thereto by preventing deposition of carbon so as not to form a Schottky contact, as well as a method for manufacturing such a silicon carbide semiconductor device. In the SiC semiconductor device, upon forming the ohmic electrode, a first metal layer made of one first metallic element is formed on one main surface of a SiC layer. Further, a Si layer made of Si is formed on an opposite surface of the first metal layer to its surface facing the SiC layer. The stacked structure thus formed is subjected to thermal treatment. In this way, there can be obtained a silicon carbide semiconductor device having an ohmic electrode adhered well to a wire by preventing deposition of carbon atoms on the surface layer of the electrode and formation of a Schottky contact resulting from Si and SiC.
    Type: Grant
    Filed: January 29, 2014
    Date of Patent: September 8, 2015
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Hideto Tamaso
  • Patent number: 8963163
    Abstract: A semiconductor device having a construction capable of achieving suppressed deterioration of electric characteristics in an insulating member is provided. An n? SiC layer, a source contact electrode formed on a main surface of the n? SiC layer, a gate electrode arranged at a distance from the source contact electrode on the main surface of the n? SiC layer, and an interlayer insulating film located between the source contact electrode and the gate electrode are provided. A rate of lowering in electric resistance in the interlayer insulating film when heating to a temperature not higher than 1200 ° C. is carried out while the source contact electrode and the interlayer insulating film are adjacent to each other is not higher than 5%.
    Type: Grant
    Filed: July 8, 2010
    Date of Patent: February 24, 2015
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Keiji Wada, Hideto Tamaso
  • Patent number: 8916462
    Abstract: A method for manufacturing a MOSFET includes the steps of: preparing a substrate made of silicon carbide; forming a drain electrode making ohmic contact with the substrate; and forming a backside pad electrode on and in contact with the drain electrode. The drain electrode formed in the step of forming the drain electrode is made of an alloy containing Ti and Si. Further, the backside pad electrode formed is maintained at a temperature of 300° C. or smaller until completion of the MOSFET. Accordingly, the manufacturing process can be efficient while achieving excellent adhesion between the electrodes.
    Type: Grant
    Filed: September 11, 2012
    Date of Patent: December 23, 2014
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Hiroyuki Kitabayashi, Hideto Tamaso, Taku Horii
  • Patent number: 8883619
    Abstract: A method for manufacturing a semiconductor device includes the steps of: preparing a substrate made of silicon carbide; forming, on one main surface of the substrate, a detection film having a light transmittance different from that of silicon carbide; confirming presence of the substrate by applying light to the detection film; and forming an active region in the substrate whose presence has been confirmed.
    Type: Grant
    Filed: November 17, 2011
    Date of Patent: November 11, 2014
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Hideto Tamaso, Hiromu Shiomi
  • Patent number: 8866156
    Abstract: A silicon carbide semiconductor device includes a silicon carbide substrate and a contact electrode. The silicon carbide substrate includes an n type region and a p type region that makes contact with the n type region. The contact electrode makes contact with the n type region and the p type region. The contact electrode contains Ni atoms and Si atoms. The number of the Ni atoms is not less than 87% and not more than 92% of the total number of the Ni atoms and the Si atoms. Accordingly, there can be provided a silicon carbide semiconductor device, which can achieve ohmic contact with an n type impurity region and can achieve a low contact resistance for a p type impurity region, as well as a method for manufacturing such a silicon carbide semiconductor device.
    Type: Grant
    Filed: May 16, 2013
    Date of Patent: October 21, 2014
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Shunsuke Yamada, Hideto Tamaso
  • Patent number: 8846531
    Abstract: To provide a method of manufacturing a semiconductor device that can be in contact with both of an n-type SiC region and a p-type SiC region and can suppress increase in contact resistance due to oxidation, a method of manufacturing a semiconductor device includes the steps of preparing a SiC layer, and forming an ohmic electrode on a main surface of the SiC layer. The step of forming the ohmic electrode includes the steps of forming a conductor layer which will become the ohmic electrode on the main surface of the SiC layer, and performing heat treatment such that the conductor layer becomes the ohmic electrode. After the step of performing the heat treatment, a temperature of the ohmic electrode when a surface of the ohmic electrode is exposed to an atmosphere containing oxygen is set to 100° C. or lower.
    Type: Grant
    Filed: July 30, 2010
    Date of Patent: September 30, 2014
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Hideto Tamaso, Keiji Wada
  • Patent number: 8847237
    Abstract: A method for manufacturing a silicon carbide semiconductor device includes the steps of preparing a silicon carbide substrate, forming a silicon dioxide film on the silicon carbide substrate, and forming an electrode containing Al and Ti to make contact with the silicon carbide substrate and the silicon dioxide film. The step of forming the electrode includes the steps of forming a metal film containing Al and Ti on the silicon carbide substrate, and heating the metal film to not less than 500° C. in an atmosphere in which oxygen gas is introduced. Thereby, the method for manufacturing the silicon carbide semiconductor device capable of improving insulation reliability of an insulating film can be provided.
    Type: Grant
    Filed: July 9, 2013
    Date of Patent: September 30, 2014
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Hideto Tamaso
  • Patent number: 8823017
    Abstract: An electrode layer lies on a silicon carbide substrate in contact therewith and has Ni atoms and Si atoms. The number of Ni atoms is not less than 67% of the total number of Ni atoms and Si atoms. A side of the electrode layer at least in contact with the silicon carbide substrate contains a compound of Si and Ni. On a surface side of the electrode layer, C atom concentration is lower than Ni atom concentration. Thus, improvement in electrical conductivity of the electrode layer and suppression of precipitation of C atoms at the surface of the electrode layer can both be achieved.
    Type: Grant
    Filed: October 19, 2011
    Date of Patent: September 2, 2014
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Hideto Tamaso
  • Publication number: 20140170841
    Abstract: The present invention provides a silicon carbide semiconductor device having an ohmic electrode improved in adhesion of a wire thereto by preventing deposition of carbon so as not to form a Schottky contact, as well as a method for manufacturing such a silicon carbide semiconductor device. In the SiC semiconductor device, upon forming the ohmic electrode, a first metal layer made of one first metallic element is formed on one main surface of a SiC layer. Further, a Si layer made of Si is formed on an opposite surface of the first metal layer to its surface facing the SiC layer. The stacked structure thus formed is subjected to thermal treatment. In this way, there can be obtained a silicon carbide semiconductor device having an ohmic electrode adhered well to a wire by preventing deposition of carbon atoms on the surface layer of the electrode and formation of a Schottky contact resulting from Si and SiC.
    Type: Application
    Filed: January 29, 2014
    Publication date: June 19, 2014
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventor: Hideto Tamaso
  • Patent number: 8729567
    Abstract: A silicon carbide semiconductor device includes a silicon carbide substrate, and a contact electrode. The silicon carbide substrate includes an n type region and a p type region in contact with the n type region. The contact electrode forms contact with the silicon carbide substrate. The contact electrode includes a first region containing TiSi, and a second region containing Al. The first region includes an n contact region in contact with the n type region and a p contact region in contact with the p type region. The second region is formed to contact the p type region and the n type region, and to surround the p contact region and the n contact region. Accordingly, there can be provided a silicon carbide semiconductor device including an electrode allowing ohmic contact with both a p type impurity region and an n type impurity region formed at a silicon carbide substrate.
    Type: Grant
    Filed: May 16, 2013
    Date of Patent: May 20, 2014
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Shunsuke Yamada, Hideto Tamaso
  • Patent number: 8716129
    Abstract: A method for manufacturing a silicon carbide semiconductor device includes the step of forming a silicon dioxide film. The step of forming an electrode includes the steps of forming a metal film containing Al and Ti on the silicon carbide substrate, and heating the metal film. The step of heating the metal film has the steps of increasing temperature of the metal film from a temperature of less than 300° C. to a temperature of not less than 300° C. and not more than 450° C. with a first temperature gradient, holding the metal film within a temperature range of not less than 300° C. and not more than 450° C. with a second temperature gradient, and increasing the temperature of the metal film to a temperature of not less than 500° C. with a third temperature gradient. The second temperature gradient is smaller than the first temperature gradient and the third temperature gradient.
    Type: Grant
    Filed: July 9, 2013
    Date of Patent: May 6, 2014
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Hideto Tamaso
  • Patent number: 8691679
    Abstract: A silicon carbide substrate has a substrate surface. A gate insulating film is provided to cover a part of the substrate surface. A gate electrode covers a part of the gate insulating film. A contact electrode is provided on the substrate surface, adjacent to and in contact with the gate insulating film, and it contains an alloy having Al atoms. Al atoms do not diffuse from the contact electrode into a portion of the gate insulating film lying between the substrate surface and the gate electrode. Thus, in a case where a contact electrode having Al atoms is employed, reliability of the gate insulating film of a semiconductor device can be improved.
    Type: Grant
    Filed: October 19, 2011
    Date of Patent: April 8, 2014
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Hideto Tamaso
  • Patent number: 8674374
    Abstract: The present invention provides a silicon carbide semiconductor device having an ohmic electrode improved in adhesion of a wire thereto by preventing deposition of carbon so as not to form a Schottky contact, as well as a method for manufacturing such a silicon carbide semiconductor device. In the SiC semiconductor device, upon forming the ohmic electrode, a first metal layer made of one first metallic element is formed on one main surface of a SiC layer. Further, a Si layer made of Si is formed on an opposite surface of the first metal layer to its surface facing the SiC layer. The stacked structure thus formed is subjected to thermal treatment. In this way, there can be obtained a silicon carbide semiconductor device having an ohmic electrode adhered well to a wire by preventing deposition of carbon atoms on the surface layer of the electrode and formation of a Schottky contact resulting from Si and SiC.
    Type: Grant
    Filed: April 14, 2010
    Date of Patent: March 18, 2014
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Hideto Tamaso
  • Publication number: 20140042461
    Abstract: A method for manufacturing a silicon carbide semiconductor device includes the steps of preparing a silicon carbide substrate, forming a silicon dioxide film on the silicon carbide substrate, and forming an electrode containing Al and Ti to make contact with the silicon carbide substrate and the silicon dioxide film. The step of forming the electrode includes the steps of forming a metal film containing Al and Ti on the silicon carbide substrate, and heating the metal film to not less than 500° C. in an atmosphere in which oxygen gas is introduced. Thereby, the method for manufacturing the silicon carbide semiconductor device capable of improving insulation reliability of an insulating film can be provided.
    Type: Application
    Filed: July 9, 2013
    Publication date: February 13, 2014
    Inventor: Hideto Tamaso
  • Publication number: 20140045322
    Abstract: A method for manufacturing a silicon carbide semiconductor device includes the step of forming a silicon dioxide film. The step of forming an electrode includes the steps of forming a metal film containing Al and Ti on the silicon carbide substrate, and heating the metal film. The step of heating the metal film has the steps of increasing temperature of the metal film from a temperature of less than 300° C. to a temperature of not less than 300° C. and not more than 450° C. with a first temperature gradient, holding the metal film within a temperature range of not less than 300° C. and not more than 450° C. with a second temperature gradient, and increasing the temperature of the metal film to a temperature of not less than 500° C. with a third temperature gradient. The second temperature gradient is smaller than the first temperature gradient and the third temperature gradient.
    Type: Application
    Filed: July 9, 2013
    Publication date: February 13, 2014
    Applicant: Sumitomo Electric Industries, Ltd.
    Inventor: Hideto Tamaso
  • Patent number: 8643065
    Abstract: A JFET is a semiconductor device allowing more reliable implementation of the characteristics essentially achievable by employing SiC as a material and includes a wafer having at least an upper surface made of silicon carbide, and a gate contact electrode formed on the upper surface. The wafer includes a first p-type region serving as an ion implantation region formed so as to include the upper surface. The first p-type region includes a base region disposed so as to include the upper surface, and a protruding region. The base region has a width (w1) in the direction along the upper surface greater than a width (w2) of the protruding region. The gate contact electrode is disposed in contact with the first p-type region such that the gate contact electrode is entirely located on the first p-type region as seen in plan view.
    Type: Grant
    Filed: December 11, 2009
    Date of Patent: February 4, 2014
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Kazuhiro Fujikawa, Hideto Tamaso, Shin Harada, Yasuo Namikawa
  • Patent number: 8623752
    Abstract: An ohmic electrode for SiC semiconductor that contains Si and Ni or an ohmic electrode for SiC semiconductor that further contains Au or Pt in addition to Si and Ni is provided. In addition, a method of manufacturing the ohmic electrode for SiC semiconductor, a semiconductor device including the ohmic electrode for SiC semiconductor, and a method of manufacturing the semiconductor device are provided.
    Type: Grant
    Filed: August 13, 2007
    Date of Patent: January 7, 2014
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Kazuhiro Fujikawa, Hideto Tamaso
  • Publication number: 20130341647
    Abstract: A silicon carbide semiconductor device includes a silicon carbide substrate, and a contact electrode. The silicon carbide substrate includes an n type region and a p type region in contact with the n type region. The contact electrode forms contact with the silicon carbide substrate. The contact electrode includes a first region containing TiSi, and a second region containing Al. The first region includes an n contact region in contact with the n type region and a p contact region in contact with the p type region. The second region is formed to contact the p type region and the n type region, and to surround the p contact region and the n contact region. Accordingly, there can be provided a silicon carbide semiconductor device including an electrode allowing ohmic contact with both a p type impurity region and an n type impurity region formed at a silicon carbide substrate.
    Type: Application
    Filed: May 16, 2013
    Publication date: December 26, 2013
    Applicant: Sumitomo Electric Industries, Ltd.
    Inventors: Shunsuke Yamada, Hideto Tamaso
  • Publication number: 20130341646
    Abstract: A silicon carbide semiconductor device includes a silicon carbide substrate and a contact electrode. The silicon carbide substrate includes an n type region and a p type region that makes contact with the n type region. The contact electrode makes contact with the n type region and the p type region. The contact electrode contains Ni atoms and Si atoms. The number of the Ni atoms is not less than 87% and not more than 92% of the total number of the Ni atoms and the Si atoms. Accordingly, there can be provided a silicon carbide semiconductor device, which can achieve ohmic contact with an n type impurity region and can achieve a low contact resistance for a p type impurity region, as well as a method for manufacturing such a silicon carbide semiconductor device.
    Type: Application
    Filed: May 16, 2013
    Publication date: December 26, 2013
    Inventors: Shunsuke Yamada, Hideto Tamaso
  • Patent number: D703162
    Type: Grant
    Filed: March 13, 2013
    Date of Patent: April 22, 2014
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Hideto Tamaso