Patents by Inventor William Chism

William Chism 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).

  • Publication number: 20070097370
    Abstract: A new method of photo-reflectance characterization of strain and active dopant in semiconductor structures has been developed for characterization of physical properties of semiconductor structures. The underlying principle of the strain and active dopant characterization technique is to measure photo-reflectance signals occurring nearby to interband transitions in the semiconductor bandstructure and which are highly sensitive to strain and/or active dopant through the effect of the nanometer scale space charge fields induced at the semiconductor surface. To attain this, the present disclosure comprises an intensity modulated pump laser beam and a continuous wave probe laser beam, focused coincident on a semiconductor structure. The pump laser provides approximately 15 mW optical power in the NIR-VIS. The pump light is amplitude modulated by a signal generator operating in the range of 100 kHz-50 MHz.
    Type: Application
    Filed: October 25, 2006
    Publication date: May 3, 2007
    Inventor: William Chism
  • Publication number: 20060098198
    Abstract: A polarization modulation photoreflectance technique has been developed for optical characterization of semiconductor electronic interfaces. By using a laser source in conjunction with polarization state modulation, a polarization modulation spectroscopy technique may be used to characterize the optical response of semiconductor materials and structures. Disclosed methods and instruments are suitable for characterization of optical signatures of electronic interfaces, including characterization of electric fields at semiconductor interfaces.
    Type: Application
    Filed: April 4, 2005
    Publication date: May 11, 2006
    Inventor: William Chism
  • Publication number: 20050017174
    Abstract: A laser stimulated atom probe for atom probe imaging of dielectric and low conductivity semiconductor materials is disclosed. The laser stimulated atom probe comprises a conventional atom probe providing a field emission tip and ion detector arrangement, a laser system providing a laser short laser pulse and synchronous electronic timing signal to the atom probe, and an optical system for delivery of the laser beam onto the field emitting tip apex. The conventional atom probe is employed in a manner similar to that used for investigation of high conductivity materials. However, the electric field is held static while the laser is pulsed to provide pulsing of the ion emission rate. The laser pulsing is accomplished in a manner similar to prior implementations of pulsed laser atom probe spectroscopy. The laser pulses provide a trigger signal to enable recording the time of flight in the atom probe.
    Type: Application
    Filed: June 30, 2004
    Publication date: January 27, 2005
    Inventor: William Chism