Detection of defects in CZ Si wafers by light scattering tomography

Abstract

Improving the quality of Czochralski method grown (CZ) Si wafers is one of the ever-lasting and very important problems to be solved. Since the keys for this improvement are effective characterization of the crystals, many ways have been developed and reported already. While light scattering tomography or laser scanning tomography (LST) to be discussed here is only one of these methods, it is very useful to detect micro-precipitates and tiny defects in the crystals such as oxygen precipitates or micro-bulk defects (MBD), aggregated vacancies (COP) and entangled dislocations in silicon crystals and misfit dislocations located between substrates and epitaxial layers.