LOW-FREQUENCY VIBRATIONAL CONTROL OF CRYSTAL GROWTH FROM MELT. E.V. Zharikov^(1,2), A.Z. Myaldun⁽²⁾, A.I. Prostomolotov⁽³⁾, N.A. Verezub⁽³⁾. ⁽¹⁾D. Mendeleev University of Chemical Technology of Russia; ⁽²⁾General Physics Institute of Russian Acad.Sci.; ⁽³⁾Institute for Problems in Mechanics of Russian Acad.Sci.

Influence of low-frequency (LF) vibrations on growth process and crystal perfection originating from vibrational control of melt flows and heat-mass transfer at crystal growth excite now rising interest of both crystallographers and hydromechanics. The practical importance of forced vibrational convection connected with the fact that the introdusing flows allow to influence on crystal quality, to control temperature field, thickness of boundary layer and to supress temperature oscillations in the melt near the interface by the complex interaction with flows of natural and thermocapillary convections.

Experiments on growth of doped yttrium-scandium-gallium garnet (Tm = 2156 K) by CZ-technique were carried out with applying of LF-vibrations with frequencies and amplitudes preliminary determined by physical modelling of the process. Microprobe analysis of grown crystals shows essential positive effect of the LF-vibrations on crystal perfection. In particular, LF-vibrations can reduce fluctuations of dopant concentration and related striations in the crystal at least by one half. They also can provide flat interface due to strong influence on heat-mass transport processes near the front of crystallization.