Schott Glas

Hans-Joerg Axmann

Gunther Wehrhan

Frank-Thomas Lentes

Burkhard Speit

Lutz Parthier

Ewald Moersen

Peter Elzner

Thorsten Reichardt

Richard Schatter

In the method for growing large-volume monocrystals crystal raw material is heated in a melting vessel with heating elements to a temperature above its melting point until a melt is formed. A monocrystal is then formed on the bottom of the melting vessel by lowering the temperature at least to the crystallization point. A solid/liquid phase boundary is formed between the monocrystal and the melt. The monocrystal grows towards the melt surface in a direction that is perpendicular to the phase boundary. A vertical axial temperature gradient is produced and maintained between the bottom of the melting vessel and its upper opening and heat inflow and/or heat outflow through side walls of the melting vessel is prevented, so that the solid/liquid phase boundary has a curvature radius of at least one meter. A crystal-growing device for performing this process is also described.

Method and device for growing large-volume oriented monocrystals

In the method and apparatus for measuring the position of the phase interface during growth of a crystal from a melt in a crystal growth container according to the VGF method an incident optical signal is propagated to the phase interface between the melt and the crystal through a window () in the container () and a received optical signal reflected from the phase interface () is measured to determine the position of the phase interface. The position of the phase interface is established from the reflected signal by triangulation with a confocal optic system, by interferometric balancing or by transit time of the optical signal. The window () is preferably mounted in a preferably tilted orientation at the end of a tube (), which is immersed in the melt ().

Method and apparatus for measuring the position of a phase interface during crystal growth

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Jena, Germany

Hans-Joerg Axmann