The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 14, 1988
Filed:
Mar. 28, 1986
Allan Rosencwaig, Danville, CA (US);
Jon Opsal, Livermore, CA (US);
Walter L Smith, Livermore, CA (US);
Therma-Wave, Inc., Fremont, CA (US);
Abstract
A method and apparatus is disclosed for detecting defect surface states in any material and in particular semiconductors. In the subject device, a periodic localized excitation is generated at the surface of the sample with an intensity modulated pump laser beam. A probe laser beam is directed to the surface of the sample and changes in the probe beam which are in phase with the modulated pump frequency are detected. In the preferred embodiment, periodic changes in the optical reflectivity of the surface of the sample induced by an intensity modulated excitation beam are detected by measuring the corresponding modulations in the reflected power of the probe beam. Any time dependence of the probe beam modulated reflectance signal is monitored. An evaluation of defect surface states is then made by investigating the time dependence of the magnitude and/or phase of this probe beam modulated reflectance signal.