Patents by Inventor Takuji Tsuzaki

Takuji Tsuzaki 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).

  • Method of growing group III nitride semiconductor crystal layer and semiconductor device incorporating group III nitride semiconductor crystal layer
    Patent number: 6194744
    Abstract: A method of growing a group III nitride semiconductor crystal layer includes a step of growing a first buffer layer composed of boron phosphide on a silicon single crystal substrate by a vapor phase growth method at a temperature of not lower than 200° C. and not higher than 700° C., a step of growing a second buffer layer composed of boron phosphide on the first buffer layer by a vapor phase growth method at a temperature of not lower than 750° C. and not higher than 1200° C., and a step of growing a crystal layer composed of group III nitride semiconductor crystal represented by general formula AlpGaqInrN (where 0≦p≦1, 0≦q≦1, 0≦r≦1, p+q+r=1) on the second buffer layer by a vapor phase growth method. A semiconductor device incorporating the group III nitride semiconductor crystal layer is provided.
    Type: Grant
    Filed: February 9, 2000
    Date of Patent: February 27, 2001
    Assignee: Showa Denko Kabushiki Kaisha
    Inventors: Takashi Udagawa, Kazutaka Terashima, Suzuka Nishimura, Takuji Tsuzaki
  • Method of growing group III nitride semiconductor crystal layer and semiconductor device incorporating group III nitride semiconductor crystal layer
    Patent number: 6069021
    Abstract: A method of growing a group III nitride semiconductor crystal layer includes a step of growing a first buffer layer composed of boron phosphide on a silicon single crystal substrate by a vapor phase growth method at a temperature of not lower than 200.degree. C. and not higher than 700.degree. C., a step of growing a second buffer layer composed of boron phosphide on the first buffer layer by a vapor phase growth method at a temperature of not lower than 750.degree. C. and not higher than 1200.degree. C., and a step of growing a crystal layer composed of group III nitride semiconductor crystal represented by general formula Al.sub.p Ga.sub.q In.sub.r N (where 0.ltoreq.p.ltoreq.1, 0.ltoreq.q.ltoreq.1, 0.ltoreq.r.ltoreq.1, p+q+r=1) on the second buffer layer by a vapor phase growth method. A semiconductor device incorporating the group III nitride semiconductor crystal layer is provided.
    Type: Grant
    Filed: March 17, 1999
    Date of Patent: May 30, 2000
    Assignee: Showa Denko K.K.
    Inventors: Kazutaka Terashima, Suzuka Nishimura, Takuji Tsuzaki, Takashi Udagawa