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:
Jul. 09, 1996
Filed:
May. 05, 1994
Izumi Fusegawa, Gunma-ken, JP;
Hirotoshi Yamagishi, Gunma-ken, JP;
Nobuyoshi Fujimaki, Gunma-ken, JP;
Yukio Karasawa, Gunma-ken, JP;
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
The evaluation of the oxide film dielectric breakdown voltage of a silicon semiconductor single crystal is caried out by cutting a wafer out of the single crystal rod, etching the surface of the wafer with the mixed solution of hydrofluoric acid and nitric acid thereby relieving the wafer of strain, then etching the surface of the wafer with the mixed solution of K.sub.2 Cr.sub.2 O.sub.7, hydrofluoric acid, and water thereby inducing occurrence of pits and scale-like patterns on the surface, determining the density of the scale-like patterns, and computing the oxide film dielectric breakdown voltage by making use of the correlating between the density of scale-like patterns and the oxide film dielectric breakdown voltage. This fact established the method of this invention to be capable of effecting an evaluation equivalent to the evaluation of the oxide film dielectric breakdown voltage of a PW wafer prepared from the single crystal rod.