Nonstationary hydrodynamic and heat/mass transfer in crystal growth MHD technologies

Yu. M. Gelfgat - L. A. Gorbunov

Institute of Physics, Latvian Academy of Sciences, Salaspils-1, LV-2169, Latvia

Abstract
The results of theoretical and experimental studies of steady and alternating electromagnetic field effects on nonstationary velocity patterns, temperature, and velocity pulsations in models of different growth processes (e.g., Cwchralski, Bridgman, THM, etc.) are presented. In this paper we discuss the features of: - effect of steady magnetic fields of different orientation due to the axis of crystal growth; - effect of an axisymmetric pulsating magnetic field generated by the inductor placed around or under the bottom of a crucible; - effect of a rotating magnetic field induced by one or two Inductors of opposite directions of rotation; - effect of a rotating magnetic field induced by one or two inductors of opposite directions of rotation; - effect of combined pulsating, rotating, and steady magnetic fields. The results obtained in the experiments on models are compared to the data obtained on growth of silicon, germanium, and indium antimonide single crystals. The interconnection of the velocity patterns occurring at MHD effect with fluctuations of temperature and velocity in melt is analyzed, at seed and crucible rotation as well. This paper presents an analysis of a possible correlation of the pulsations of temperature, velocity, and concentration in melt and the occurrence and distribution of macro- and micro-defects in growing single crystals.