Multi-stage side heater in vertical gradient freezing crystal growing furnace

Abstract

The invention discloses a multi-stage side heater in a vertical gradient freezing crystal growing furnace. The multi-stage side heater comprises a graphite sleeve, and an upper heater and a lower heater positioned in the graphite sleeve, wherein the upper heater in the graphite sleeve is connected with a graphite electrode fixed on an upper furnace cover plate, and is connected with the graphite sleeve through boron nitride; or the upper heater is supported by a graphite block, and the graphite sleeve is connected with an electrode fixed on the upper furnace cover plate; the lower heater is arranged in the graphite sleeve and is supported by a graphite block; and the graphite sleeve is connected with the electrode fixed on the upper furnace cover plate, and is fixed on the upper furnace cover plate through a screw. The invention has the advantages that: a suspended side heating system can entirely move upwards together with a furnace cover, and is entirely detached, and an insulating layer outside the heating system is not needed to be detached, so equipment maintenance, material loading and material taking are greatly facilitated; and a long plate electrode is adopted, a complete graphite cylinder is formed outside the side heating system, and the graphite cylinder can absorb, reradiate and reflect heat of the heater, so the heat utilization ratio is improved, and a thermal field has higher symmetry and stability.

Description

technical field [0001] The invention relates to the field of crystal growth, in particular to the design of a heating system when a vertical gradient solidification technique (VGF) is used to grow a single crystal. Background technique [0002] VGF (Vertical Gradient Solidification) technology has become one of the mainstream technologies for growing large-diameter, low-dislocation single crystals. Its biggest advantage is that it can form a small temperature gradient at the solid-liquid interface of crystal growth. Ensuring the symmetry of the thermal field and maintaining the stability of the thermal field is the key to the design of the VGF thermal field. In the crystal system, the side heater is the main heater, which determines the nature of the thermal field, so the design of the side heating system is one of the core contents of the entire crystal growth system. At present, the side heating of the VGF single crystal growth system adopts coil heating and high-purity g...

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Problems solved by technology

This assembly method is simple, but when it is necessary to put in raw materials, take out materials, and disassemble and maintain the heater, it is necessary to remove

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