Enhanced VGF growth of single- and multi-crystalline semiconductors using pulsed TMF

N. Dropka - Ch. Frank-Rotsch

Leibniz-Institute for Crystal Growth, Max-Born-Str. 2, D-12489 Berlin, Germany

Abstract
Control of solid/liquid interface morphology, dopant spatial and thermal azimuthal uniformity at the melt boundaries is a key for a success of the vertical gradient freeze (VGF) crystal growth of semiconductors. To assure fast achievement of favorable flow, temperature and concentration patterns during the entire process, we propose electromagnetic stirring by pulsed travelling magnetic fields (TMFs) induced by either side or top KRISTMAG^{\textregistered} heater-magnet-modules (HMMs). The pulsed Lorentz forces were produced by a sinusoidal ac magnitude modulation. Pros and cons of the proposed stirring and interface shaping approach were appraised by 3D CFD and magnetic numerical studies of directional solidification (DS) of multi-crystalline silicon (mc-Si) and VGF-gallium arsenide (GaAs) single crystals at the industrial scale. Figs 6, Refs 5.