Patents by Inventor Hiroshi Matagi

Hiroshi Matagi 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: 5395792
    Abstract: There is provided a process for fabricating a highly reliable semiconductor laser device operable at a low current with an increased yield, which process includes the steps of: (a) forming a lower clad layer on a semiconductor substrate; (b) forming an active layer of a material larger in refractive index and smaller in forbidden band width than the lower clad layer; (c) forming a first upper clad layer of a material smaller in refractive index and larger in forbidden band width than the active layer; (d) forming an etch stop layer made of GaAs on the first upper clad layer; (e) forming a current-blocking layer of a material smaller in refractive index and larger in forbidden band width than the first upper clad layer; (f) forming a stripe cavity by etching at least a portion of the current-blocking layer down to the etch stop layer; (g) evaporating the etch stop layer remaining in the stripe cavity; (h) forming a second upper clad layer of a material smaller in refractive index and larger in forbidden band w
    Type: Grant
    Filed: June 1, 1994
    Date of Patent: March 7, 1995
    Assignee: Rohm Co., Ltd.
    Inventors: Katsuhiko Ikawa, Hiroshi Matagi
  • Patent number: 5394421
    Abstract: A highly reliable semiconductor laser device capable of exhibiting a good current-light output characteristic and a fabrication process therefore is provided. The semiconductor laser device is provided with a step in a region adjacent a laser-light-emitting edge to separate an upper electrode into two, one of which is located adjacent the laser-light-emitting edge and does not allow current to flow in the underlying portion even if the other is applied with voltage, thereby forming a current-noninjection region in the region adjacent the later-light-emtting edge. Due to such an arrangement, deterioration of device characteristics due to local heat generation can be assuredly prevented without changing the structure adjacent the active layer and the current-confining structure which dominate the characteristics of the semiconductor laser.
    Type: Grant
    Filed: December 6, 1993
    Date of Patent: February 28, 1995
    Assignee: Rohm Co., Ltd.
    Inventors: Katsuhiko Ikawa, Yukio Shakuda, Hiroshi Matagi