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:
Aug. 22, 1995
Filed:
Sep. 28, 1993
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
The substitutional carbon concentration in a silicon single crystal is determined by determining by FT-IR the infrared absorbance spectrum using as a reference a substantially carbon-free silicon single crystal having substantially the same degree of free carrier absorption and produced by the same process as the sample. A subtraction factor used in the determination is calculated from the infrared absorbance spectra of the sample and the reference. A subtraction spectrum indicating the difference between the sample and the reference at the relevant wave number for carbon is computed, and the carbon concentration in the sample is determined from the distance of the absorption peak of the subtraction spectrum of the localized vibration of substitutional carbon in the sample from a base line of the subtraction spectrum. An FT-IR carbon concentration determination apparatus embodying the method is also disclosed.