METHOD AND EQUIPMENT FOR AUTOMATICALLY MEASURING SUBSTITUTIONAL CARBON CONCENTRATION IN SILICON SINGLE CRYSTAL

摘要

PURPOSE:To provide a method and equipment for measuring the substitutional carbon concentration in a silicon single crystal accurately and automatically. CONSTITUTION:When the substitutional carbon concentration in a silicon single crystal is measured using FT-IR method (Fourier Transform Infrared spectrometry), a differential coefficient is calculated basing on the infrared absorbance spectrum obtained from a sample, i.e., a silicon single crystal, and that obtained from a non-carbon silicon single crystal (reference) having substantially identical free carrier absorbance produced by same method as the sample. The differential coefficient is employed in the determination of a differential absorbance spectrum from both infrared absorbance spectrums. Substitutional carbon concentration in the sample is then determined basing on the distance between a base line and a local oscillation absorption peak of the substitutional carbon in the differential absorbance spectrum.