NITROGEN IN THIN SILICON WAFERS DETERMINED BY INFRARED SPECTROSCOPY

摘要

A procedure is developed for differential spectroscopic measurements with an improved photometric quality. A relatively quick periodical change of the analyzed and the reference samples was employed accompanied with a multiple spectra registration and mathematical treatment. As a result, a differential transmission spectrum was generated where the effect of the low frequency noise as well as a systematic drift during the accumulation of the spectral data were substantially reduced. The procedure was successfully applied to the determination of nitrogen in 200 mm - and 300 mm CZ Si wafers with a thickness of 730 urn and 780 am, A detection limit of approximately 3 * 10~(14) atoms/cm was achieved.