Patents by Inventor Yukiharu Kitazawa

Yukiharu Kitazawa 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 for diffusing boron into semiconductor wafers
    Patent number: 5208185
    Abstract: In a boron diffusion process, a multiplicity of semiconductor wafers and pyrolytic boron nitride dopant disks are placed in a diffusion tube kept in an inert atmosphere at a high temperature, and boron diffusion is performed with hydrogen injection, the initial concentration of hydrogen in the diffusion tube being a very low range of 0.05% by volume at maximum. The result is that it is possible to improve dispersion of sheet resistivity (.rho.s) of the silicon wafer surface remarkably and to suppress occurrence of lattice defects.
    Type: Grant
    Filed: March 17, 1992
    Date of Patent: May 4, 1993
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Yoshiyuki Mori, Yukiharu Kitazawa, Masahide Kojima, Tomoyuki Sakai, Eiichi Nishijo, Nobuhiro Tsuda, Tadayuki Ebe