Patents Assigned to Solid State Measurments, Inc.
  • Patent number: 6836139
    Abstract: A charge carrier lifetime of a semiconductor wafer is measured by contacting an electrically conductive measurement probe to a surface of a semiconductor wafer to form a capacitor. A DC voltage having an AC voltage superimposed thereon is applied to the capacitor and the DC voltage is swept between a first voltage and a second voltage. At the second voltage, the semiconductor wafer adjacent the contact between the measurement probe and the surface of the semiconductor wafer is exposed to a light pulse. After the light pulse terminates, a change in the capacitance of the capacitor over time is determined. From the thus determined change in capacitance, a charge carrier lifetime of the semiconductor wafer is determined.
    Type: Grant
    Filed: October 22, 2002
    Date of Patent: December 28, 2004
    Assignee: Solid State Measurments, Inc.
    Inventor: William H. Howland