Patents by Inventor Keiji Miyashita

Keiji Miyashita 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: 6225650
    Abstract: A GaN group crystal base member comprising a base substrate, a mask layer partially covering the surface of said base substrate to give a masked region, and a GaN group crystal layer grown thereon to cover the mask layer, which is partially in direct contact with the non-masked region of the base substrate, use thereof for a semiconductor element, manufacturing methods thereof and a method for controlling a dislocation line. The manufacturing method of the present invention is capable of making a part in the GaN group crystal layer, which is above a masked region or non-masked region, have a low dislocation density.
    Type: Grant
    Filed: March 24, 1998
    Date of Patent: May 1, 2001
    Assignee: Mitsubishi Cable Industries, Ltd.
    Inventors: Kazuyuki Tadatomo, Hiroaki Okagawa, Youichiro Ohuchi, Keiji Miyashita, Kazumasa Hiramatsu, Nobuhiko Sawaki, Katsunori Yahashi, Takumi Shibata
  • Patent number: 5710440
    Abstract: A semiconductor light emitting element comprising an n-type semiconductor substrate and a light emitting part comprising an n-type cladding layer composed of an InGaAlP compound semiconductor material, an active layer and a p-type cladding layer formed in that order from the substrate side by double heterojunction, wherein said semiconductor light emitting element satisfies at least one of the following conditions:A. the thickness of said active layer being greater than 0.75 .mu.m and not more than 1.5 .mu.m, andB. the thickness of said p-type cladding layer being 0.5 .mu.m-2.0 .mu.m. According to the light emitting element of the present invention, an overflow of electron into the p-type cladding layer can be suppressed by setting the thickness of the active layer and the p-type cladding layer to fall within the above-mentioned specific ranges, as a result of which the element shows luminous efficiency peaked within the specified range.
    Type: Grant
    Filed: February 12, 1996
    Date of Patent: January 20, 1998
    Assignee: Mitsubishi Cable Industries, Ltd.
    Inventors: Hiroaki Okagawa, Takayuki Hashimoto, Keiji Miyashita, Tomoo Yamada, Kazuyuki Tadatomo
  • Patent number: 5635733
    Abstract: In the light emitting element comprising an n-type semiconductor substrate, a lower electrode formed on the lower surface of the substrate, and a light emitting part having a pn junction, which is composed of an InGaAlP compound semiconductor material, a p-type current diffusing layer and an upper electrode which are laminated on the upper surface of the substrate in that order from the substrate side, the improvement wherein a carrier concentration of the current diffusing layer is lower on a light emitting part side thereof than that on an upper electrode side thereof, and at least the upper electrode side of the current diffusing layer is composed of GaP. By employing such structure, diffusion of the dopant to a light emitting part can be suppressed even when the carrier concentration of the upper part of the current diffusing layer is set to be higher, thereby affording a lower resistance of the current diffusing layer as a whole.
    Type: Grant
    Filed: February 16, 1996
    Date of Patent: June 3, 1997
    Assignee: Mitsubishi Cable Industries, Ltd.
    Inventors: Hiroaki Okagawa, Takayuki Hashimoto, Keiji Miyashita, Tomoo Yamada, Kazuyuki Tadatomo