Directional solidification from the melt is the favoured process to produce bulk crystalline materials with major applications in the electronics industry. The demand for substrates to be used for the growth of active epitaxial layers has been driving a continuous improvement in terms of samples size and quality. The most spectacular result is that, silicon crystals of up to 40 cm in diameter and 1 m long can now be suppress "routinely" manufactured. Crystal growth of compound semiconductors is significantly more difficult, and the maximum sample size is much smaller. Such a limitation is one of the reasons that has limited the development of gallium arsenide based high speed electronics as well as the use of peculiar III-V and 11-VI materials (e.g. InP or CdTe) in optoelectronic applications. Apart from semiconductors, directional solidification has also been applied to other classes of materials, such as metals, halides and various types of oxides (Hurle 1994).