Procedure for the growth of single crystals without crucible and thus without contaminations caused by crucible material.
In this process, a narrow zone of a poly-crystalline bar is melted by means of a high-frequency heater and recrystallized, with the melting zone moving upwards with the heater. This process is repeated and any contamination is removed from the crystals since the solubility of foreign matter is usually higher in the liquid phase. In this process, the contaminants are transported upwards together with the melt. This process produces ver pure silicon and germanium crystals, for example.