4. Zone Refining
Zone melting is apllying for deep cleaning of polycrystalline Germanium. It is the method of the horizontal directional crystallization which is carried out by crucible way.
This method is based on various solubility of impurities in firm and liquid phases. During the ingot moving via the heater, the melted zone moves on along the ingot. Dissolved impurities collect in fusion and transfer to the end of ingot. Process is carried out in the atmosphere of flowing hydrogen on multitube furnaces with induction heating.
The final product of process is germanium polycrystalline zonerefined with a form of cross section in the shape of callote or trapeze. This product is the initial raw material for growing of monocrystals or for alloys production, dusting and epitaxy.