Patents by Inventor Yoshihiro Okusa

Yoshihiro Okusa 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: 6316339
    Abstract: On a silicon substrate 1 is provided a silicon oxide film 2, on which a polycrystalline silicon film 3 is formed by a low pressure CVD method at a monosilane partial pressure of no more than 10 Pa and a film formation temperature of no lower than 600° C. The polycrystalline silicon film is doped with an impurity such as phosphorus in a concentration of 1×1020 atoms/cm3 to 1×1021 atoms/cm3 to form a phosphosilicate glass film 6, and after removing it, the polycrystalline silicon film is thermally oxidized in an oxidative atmosphere to form a dielectric film 5 on the surface. A polycrystalline silicon film 4 is formed on the dielectric film 5, which is treated as the oriented polycrystalline silicon film 3a to form an oriented polycrystalline silicon film 4a. The oriented polycrystalline silicon film 4a as an upper electrode and the oriented polycrystalline silicon film 3a as a lower electrode are wired to obtain a semiconductor device having a capacitor.
    Type: Grant
    Filed: February 25, 2000
    Date of Patent: November 13, 2001
    Assignee: Asahi Kasei Microsystems Co., Ltd.
    Inventors: Yoshihiro Okusa, Tatsuya Yamauchi
  • Patent number: 6069388
    Abstract: On a silicon substrate 1 is provided a silicon oxide film 2, on which a polycrystalline silicon film 3 is formed by a low pressure CVD method at a monosilane partial pressure of no more than 10 Pa and a film formation temperature of no lower than 600.degree. C. The polycrystalline silicon film is doped with an impurity such as phosphorus in a concentration of 1.times.10.sup.20 atoms/cm.sup.3 to 1.times.10.sup.21 atoms/cm.sup.3 to form a phosphosilicate glass film 6, and after removing it, the polycrystalline silicon film is thermally oxidized in an oxidative atmosphere to form a dielectric film 5 on the surface. A polycrystalline silicon film 4 is formed on the dielectric film 5, which is treated as the oriented polycrystalline silicon film 3a to form an oriented polycrystalline silicon film 4a. The oriented polycrystalline silicon film 4a as an upper electrode and the oriented polycrystalline silicon film 3a as a lower electrode are wired to obtain a semiconductor device having a capacitor.
    Type: Grant
    Filed: December 3, 1997
    Date of Patent: May 30, 2000
    Assignee: Asahi Kasei Microsystems Co., Ltd.
    Inventors: Yoshihiro Okusa, Tatsuya Yamauchi