Characterization of striations in silicon wafers by a multipass Fabry-Perot Rayleigh-Brillouin scattering spectrometer

Abstract

Swirls and oxidation stacking faults (OSF) ring-bands in the near surface region of Si crystals have been detected and characterized by a 180° backscattering Rayleigh-Brillouin spectrometer using an argon-ion laser as its light source. In FZ Si wafers with swirls, the central region exhibits high scattered light with random undulation, the peripheral region with swirls shows a periodic undulation of scattered light intensity, while the region in-between is a nearly uniform zone of low scattered light intensity. In contrast to this, the CZ Si wafers with OSF ring-bands display a low uniformly scattered light background with a high undulated scattered light zone corresponding to the OSF ring-band. The scattered light intensity and its structure in the OSF ring-band vary with the heat-treatment conditions. The features of scattered light detected by the scattering spectrometer are discussed.