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:
Jan. 16, 1996
Filed:
Apr. 11, 1994
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
A silicon single crystal for use as semiconductor is grown by supplying, to a seed rod of single-crystal silicon, hydrochloride gas and silicon formed by admixing at least one chlorosilane gas selected from the group consisting of dichlorosilane, trichlorosilane and tetrachlorosilane with hydrogen gas at a high temperature to grow single-crystal silicon on the seed rod while etching the growing single-crystal silicon with the hydrochloride gas. The silicon single crystal is irradiated with laser rays so that the energy of the laser rays on the irradiated surface of the crystal ranges from 3100 to 3358 mW/cm.sup.2 and then spectra emitted by the crystal are optoelectrically determined to quantify the ultratrace elements present in the silicon single crystal. Moreover, the amounts of these ultratrace elements are reduced to those of ultratrace elements present in the chlorosilane gas.