Crystallization at high temperature
General aim [BYR 02]
In general, the aim is to obtain the crystals of inorganic compounds with a high melting point.
For jewelry, “large crystals”, whose size is in the order of a centimeter, are sought. This result can be reached by whichever one of the following three methods is appropriate:
- - the Verneuil method;
- - the Czochralski method;
- - the thermal gradient method.
For electronics, we manufacture semi-conductor “films” that are monocrystals in a thin layer.
Uses can also be found for crystals sized in the order of a millimeter.
The Verneuil method
The powdered material is treated by a welding torch that turns it into fine droplets, which are then deposited on the crystal by forming a small pool. This pool feeds the crystal.
The Czochralski method
A crystal that is initially small in size is brought into contact with the surface of the product in a melted state, which then feeds the crystal. The growing crystal is moved by rotating its vertical axis, and in addition, rises slowly as it develops. Ultimately, the crystal has a cylindrical form that can be cut into fine slices (silicon, semi-conductors). This process requires considerable expertise.