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. 19, 1995
Filed:
Jun. 16, 1993
Yoichiro Ogita, Aikawa, JP;
Tateo Kusama, Gorikida, JP;
School Judicial Person Ikutoku Gakuen, Kanagawa, JP;
Semitex Co., Ltd., Tokyo, JP;
Abstract
A method of and apparatus for evaluating the lifetime of a semiconductor material which is capable of measuring, in a non-contact and non-destructive manner, the lifetime of a surface thin-layer portion so as to evaluate the quality of a semiconductor device formed of an epitaxial wafer or a thin device-forming material. Light within a short-wavelength region is radiated for a short period of time on the surface of a semiconductor material to be evaluated, thereby generating carriers effectively on the surface and in a surface thin-layer. An electromagnetic wave within a millimeter to sub-millimeter wave region is projected onto the surface, and a wave reflected from the surface is measured to obtain a decay curve of the carriers. On the basis of the carrier decay curve, the lifetime of the surface as well as a surface thin-layer portion of the semiconductor material is evaluated.