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:
May. 03, 1994
Filed:
Sep. 22, 1993
Applicant:
Inventors:
Assignee:
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
437141 ; 437 12 ; 437248 ; 437914 ; 148D / ;
Abstract
In a method of preparing a diffused silicon device substrate for use in the fabrication of a MOS power device, a drive-in diffusion step is followed by a thermal donor formation heat treatment which is achieved by heating the silicon device substrate at a temperature from 400.degree. to 500.degree. C. for 1 to 20 hours and in a gas atmosphere containing oxygen gas, and subsequently a thermal donor formation retarding heat treatment is performed by heating the silicon device substrate at a temperature of from 600.degree. to 700.degree. C. for 8 to 24 hours in a gas atmosphere containing oxygen gas.