Patents by Inventor Atsuto Sakata

Atsuto Sakata 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).

  • Epitaxial wafer
    Patent number: 5705423
    Abstract: An improved and highly productive method is proposed for the preparation of an epitaxial wafer (EPW) consisting of a single crystal silicon wafer as the substrate having a mirror-polished surface and an epitaxial layer of silicon formed on the mirror-polished surface of the substrate by the method of vapor-phase growing. Different from conventional methods in which the mirror-polishing of the substrate surface is conducted in several steps including, usually, the primary, secondary and finish polishing steps taking a great deal of labor and time, it has been unexpectedly discovered that an EPW having excellent properties not inferior to those conventional EPWs can be obtained by conducting the mirror-polishing with the primary polishing only omitting the subsequent steps provided that the thus mirror-polished surface of the substrate has a surface roughness RMS in the range from 0.3 to 1.2 mm.
    Type: Grant
    Filed: November 14, 1995
    Date of Patent: January 6, 1998
    Assignee: Shin-Etsu Handotai Co., Ltd.
    Inventors: Atsuto Sakata, Hisashi Masumura, Hideo Kudo