Single crystal pulling without temperature programming

A variation of the `melted layer' method of growing single crystals is described by which the melt is kept at a constant position on the heater. In this way the temperature distribution within the melt remains unchanged with time, provided there is no change in the heater temperature. In the `melted layer' method, Horn achieved this by lowering the heater, while here the crucible is lifted and the melt, reduced in volume by the amount of the pulled crystal, is replenished by melting the polycrystalline material. The method was tested experimentally with germanium. A crystal of germanium was increased in diameter from the seed to a certain convenient cross section, which thereafter remained reasonably constant in spite of the lack of temperature programming and rather marked temperature variations.