Patents by Inventor Tsutomu Michitsuta

Tsutomu Michitsuta 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).

  • Process of manufacturing a semiconductor device
    Patent number: 7919415
    Abstract: A process of manufacturing a semiconductor device includes the steps of forming a stacked structure of a first III-V compound semiconductor layer containing In and having a composition different from InP and a second III-V compound semiconductor layer containing In. The second III-V compound semiconductor layer is formed over the first III-V compound semiconductor layer and growing an InP layer at regions adjacent the stacked structure to form a stepped structure of InP. The process further includes the step of wet-etching the stepped structure and the second III-V compound semiconductor layer using an etchant containing hydrochloric acid and acetic acid to remove at least the second III-V compound semiconductor layer.
    Type: Grant
    Filed: October 29, 2007
    Date of Patent: April 5, 2011
    Assignee: Fujitsu Quantum Devices Limited
    Inventors: Takayuki Watanabe, Tsutomu Michitsuta, Taro Hasegawa, Takuya Fujii
  • Process of manufacturing a semiconductor device
    Publication number: 20080070419
    Abstract: A process of manufacturing a semiconductor device includes the steps of forming a stacked structure of a first III-V compound semiconductor layer containing In and having a composition different from InP and a second III-V compound semiconductor layer containing In. The second III-V compound semiconductor layer is formed over the first III-V compound semiconductor layer and growing an InP layer at regions adjacent the stacked structure to form a stepped structure of InP. The process further includes the step of wet-etching the stepped structure and the second III-V compound semiconductor layer using an etchant containing hydrochloric acid and acetic acid to remove at least the second III-V compound semiconductor layer.
    Type: Application
    Filed: October 29, 2007
    Publication date: March 20, 2008
    Applicant: FUJITSU QUANTUM DEVICES LIMITED
    Inventors: Takayuki Watanabe, Tsutomu Michitsuta, Taro Hasegawa, Takuya Fujii
  • Process of manufacturing a semiconductor device
    Patent number: 7303933
    Abstract: A process of manufacturing a semiconductor device includes the steps of forming a stacked structure of a first III-V compound semiconductor layer containing In and having a composition different from InP and a second III-V compound semiconductor layer containing In. The second III-V compound semiconductor layer is formed over the first III-V compound semiconductor layer and growing an InP layer at regions adjacent the stacked structure to form a stepped structure of InP. The process further includes the step of wet-etching the stepped structure and the second III-V compound semiconductor layer using an etchant containing hydrochloric acid and acetic acid to remove at least the second III-V compound semiconductor layer.
    Type: Grant
    Filed: June 20, 2005
    Date of Patent: December 4, 2007
    Assignee: Fujitsu Quantum Devices Limited
    Inventors: Takayuki Watanabe, Tsutomu Michitsuta, Taro Hasegawa, Takuya Fujii
  • Process of manufacturing a semiconductor device
    Publication number: 20050245089
    Abstract: A process of manufacturing a semiconductor device includes the steps of forming a stacked structure of a first III-V compound semiconductor layer containing In and having a composition different from InP and a second III-V compound semiconductor layer containing In. The second III-V compound semiconductor layer is formed over the first III-V compound semiconductor layer and growing an InP layer at regions adjacent the stacked structure to form a stepped structure of InP. The process further includes the step of wet-etching the stepped structure and the second III-V compound semiconductor layer using an etchant containing hydrochloric acid and acetic acid to remove at least the second III-V compound semiconductor layer.
    Type: Application
    Filed: June 20, 2005
    Publication date: November 3, 2005
    Applicant: Fujitsu Quantum Devices Limited
    Inventors: Takayuki Watanabe, Tsutomu Michitsuta, Taro Hasegawa, Takuya Fujii
  • Process of manufacturing a semiconductor device
    Patent number: 6924162
    Abstract: A process of manufacturing a semiconductor device includes the steps of forming a stacked structure of a first III-V compound semiconductor layer containing In and having a composition different from InP and a second III-V compound semiconductor layer containing In. The second III-V compound semiconductor layer is formed over the first III-V compound semiconductor layer and growing an InP layer at regions adjacent the stacked structure to form a stepped structure of InP. The process further includes the step of wet-etching the stepped structure and the second III-V compound semiconductor layer using an etchant containing hydrochloric acid and acetic acid to remove at least the second III-V compound semiconductor layer.
    Type: Grant
    Filed: February 14, 2002
    Date of Patent: August 2, 2005
    Assignee: Fujitsu Quantum Devices Limited
    Inventors: Takayuki Watanabe, Tsutomu Michitsuta, Taro Hasegawa, Takuya Fujii
  • Process of manufacturing a semiconductor device
    Publication number: 20020111034
    Abstract: A process of manufacturing a semiconductor device includes the steps of forming a stacked structure of a first III-V compound semiconductor layer containing In and having a composition different from InP and a second III-V compound semiconductor layer containing In. The second III-V compound semiconductor layer is formed over the first III-V compound semiconductor layer and growing an InP layer at regions adjacent the stacked structure to form a stepped structure of InP. The process further includes the step of wet-etching the stepped structure and the second III-V compound semiconductor layer using an etchant containing hydrochloric acid and acetic acid to remove at least the second III-V compound semiconductor layer.
    Type: Application
    Filed: February 14, 2002
    Publication date: August 15, 2002
    Applicant: Fujitsu Quantum Devices Limited
    Inventors: Takayuki Watanabe, Tsutomu Michitsuta, Taro Hasegawa, Takuya Fujii