Patents Assigned to Niigata Univerasity
  • Patent number: 8578777
    Abstract: A quantitative evaluation method, a method for manufacturing a silicon wafer, and a silicon wafer manufactured by the method, enabling more efficient evaluation of the concentration of atomic vacancies existing in a silicon wafer. The quantitative evaluation method includes steps of: oscillating, in a state in which an external magnetic field is applied to a silicon wafer (26) while keeping the silicon wafer (26) at a constant temperature, an ultrasonic wave pulse and receiving a measurement wave pulse obtained after the ultrasonic wave pulse is propagated through the silicon wafer (26) for detecting a phase difference between the ultrasonic wave pulse and the measurement wave pulse; and calculating an elastic constant from the phase difference. The external magnetic field is changed to calculate the elastic constant corresponding to a change in the external magnetic field for evaluating a concentration of atomic vacancies in the silicon wafer (26).
    Type: Grant
    Filed: August 19, 2010
    Date of Patent: November 12, 2013
    Assignee: Niigata Univerasity
    Inventors: Terutaka Goto, Hiroshi Kaneta, Yuichi Nemoto, Mitsuhiro Akatsu