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:
Sep. 04, 1990
Filed:
Mar. 25, 1988
Nicholas Bottka, Burke, VA (US);
D Kurt Gaskill, Alexandria, VA (US);
Robert Glosser, Plano, TX (US);
Other;
Abstract
An apparatus and method for non-destructive measuring of local carrier concentration and bandgap in a semiconductor such as gallium arsenide or gallium aluminum arsenide. A high energy source of photons, e.g. a laser, photo injects carriers on the surface of the semiconductor causing a change in the semiconductor's surface photo reflectance. The fractional change in photo reflectance is measured for a plurality of the photon energies sufficient to identify several Franz-Keldysh peaks, and the photon energies corresponding to these peaks. This information is used to infer the local electric field strength and carrier concentration of the semiconductor as well as semiconductor's bandgap. By noting variations in these parameters throughout the bulk semiconductor, one can identify fatal fabrication flaws in the semiconductor crystal before time and money is expended to fabricate complicated semiconductor architectures in the crystal.