Crystal Growing Systems Gmbh

Siltronic Ag

Axel Vonhoff

Burkhard Altekrüger

Erich Tomzig

Dieter Knerer

Andreas Mühe

Stefan Henkel

A pulling apparatus and a method with which especially heavy crystals () can be pulled using the Czochralski method utilizing the pulling apparatus. For this purpose the neck () of the crystal () has an enlargement () beneath which extends the support device. This device includes latches (), which are moved from a resting position into an operating position in which the latches () extend beneath the enlargement (). Each latch () is supported on the base body such that it is swivellable about a pivot axis () and can assume two stable positions, namely the resting position and the operating position. Each of these positions is defined by a stop on the base body. When the latch rests on the one stop, its center of gravity, viewed from the neck (), is located on the other side of the pivot axis (). When the latch rests on the other stop, the center of gravity is located on this side of the pivot axis (). The actuation of the latches () takes place with actuation means disposed stationarily in the apparatus.

Crystal pulling apparatus and method for the production of heavy crystals

The invention relates to producing a melt that is as homogeneous as possible, to which fresh material in the form of granulate is continuously supplied. Since the granulate is cooler than the melt, heat sinks form that are especially pronounced when the granulate forms clumps in the melt. Therefore, the invention relates to a means for distributing the granulate. In one aspect, the means are inductors arranged outside the melting crucible that generate an alternating magnetic field in the melt. In this way, electrical currents are induced there that, in turn, cause the material flows. In one aspect, the inductors are arranged and controlled in such a way that a rapid distribution of the granulate is effected and thus its rapid melting. In this way, good homogeneity is achieved, especially in the center of the melt where the removal of the melted material also occurs.

Melting crucible

The invention presented here relates to a crystal growing equipment. It is equipped in general with a resistance heater for heating a melt () as well as with field coils, which generate alternating magnetic field in a crucible, with which flows can be induced in the melt (). The invention is so designed that the resistance heaters are also devised to function as the field coils, that is, they are built of a hollow cylindrical body (), in which, by means of a surrounding slit () which winds around it, a spiral-shaped single layer current path is formed. This has the advantage that the current needed for the electrical heating in the equipment is also used for the generation of the magnetic field. Thus, neither separate field coils nor a separate current supply is necessary. Further, the resistance heater, which serves as the field coil arranged as a coil array, is high temperature resistant and surrounds the immediate hot core zone of the equipment and thus the region of the melt. Thus the volume, in which the magnetic field must be generated, is minimized. Further, the alternating magnetic field does not need to penetrate through the wall of the vessel of the crystal growing equipment, hence the vessel can be designed as a steel boiler in conventional manner.

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Friesenheim-Oberweiler, Germany

Axel Vonhoff