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:
Oct. 11, 1988
Filed:
Feb. 24, 1987
Richard B Bylsma, Red Bank, NJ (US);
Alastair M Glass, Rumson, NJ (US);
American Telephone and Telegraph Company, AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
Semi-insulating wafers such as semi-insulating gallium arsenide wafers are commonly utilized in the fabrication of semiconductor devices, e.g., lasers and optical detectors. The quality of wafer electrical properties is determined before device processing by an optical technique. In this technique a refractive index change is induced with incident light and the rate of decay of this refractive index change upon change of incident light intensity is monitored with a second beam. The rate of decay is directly related to electrical properties such as resistivity. Subsequent processing is then based on this measurement.