Lower furnace structure of pseudo-single crystal ingot furnace

Abstract

The invention belongs to the technical field of single crystal furnaces and in particular relates to a lower furnace structure of a pseudo-single crystal ingot furnace. The lower furnace structure ofthe pseudo-single crystal ingot furnace comprises a lower furnace bottom shell, an assembling support base, a support base and a support column, wherein the lower furnace bottom shell is internally provided with a guide track transmission mechanism, an air door mechanism and a water cooling mechanism; the air door mechanism comprises a heat door; the heat door of the air door mechanism is driven by the guide track transmission mechanism; a heating mechanism is arranged corresponding to the air door mechanism inside the lower furnace bottom shell; overflowing mechanisms are arranged around theperiphery of the heating mechanism; the overflowing mechanisms are communicated with an overflowing alarm mechanism through drainage holes. The lower furnace structure has the beneficial effects of being simple in structure and convenient to use; bottom seed crystals can be effectively protected; due to adoption of a guide groove, a silicon liquid can rapidly reach a guide position, the reaction time is shortened, abnormity can be rapidly and effectively processed, overflowing wires are respectively connected with thermocouples, and temperature abnormity caused by overflowing of the silicon liquid can be rapidly fed back; in addition, due to adoption of the bottom overflowing wires at the lower furnace bottom shell, silicon overflowing can be accurately judged.

Description

technical field [0001] The invention belongs to the technical field of single crystal furnaces, and in particular relates to a lower furnace body mechanism of a quasi-single crystal ingot casting furnace. Background technique [0002] The quasi-single crystal ingot furnace is an inert gas (nitrogen, helium-based) environment, using a graphite heater to melt polycrystalline silicon and other polycrystalline materials. It is based on the quasi-single crystal ingot furnace process to grow dislocation-free single crystal Quasi-single crystal (MonoLike) is a process based on polycrystalline ingot casting. When growing crystals, monocrystalline seed crystals are used partly to obtain polycrystalline silicon wafers that are similar in appearance and electrical properties to single crystals. This method of ingot casting The technology of forming monocrystalline silicon only consumes more power than ordinary polycrystalline silicon, and the quality of the produced monocrystalline sil...

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Problems solved by technology

[0002] The quasi-single crystal ingot furnace is an inert gas (nitrogen, helium-based) environment, using a graphite heater to melt polycrystalline silicon and other polycrystalline materials. It is based on the quasi-single crystal ingot furnace process to grow dislocation-free single crystal Quasi-single crystal (MonoLike) is a process based on polycrystalline ingot casting. When growing crystals, monocrystalline seed crystals are used partly to obtain polycrystalline silicon wafers that are similar in appearance and electrical properties to single crystals. This method of ingot casting The technology of forming monocrystalline silicon only consumes more power than ordinary polycrystalline silicon, and the quality of the produced monocrystalline silicon is close to that of Czochralski monocrystalline silicon. Simply put, this technology is to produce monocrystalline silicon at the cost of polycrystalline silicon. , most of the current mass-produced quasi-single crystal technology is ingot casting with seed crystals. In this technology, the seed crystal and silicon material doping elements are first placed in the crucible. The seed crystal is generally located at the bottom of the crucible, and then the silicon material is heated and melted. Keep the seed crystal from being completely melted, and finally control the temperature drop, adjust the temperature gradient of the solid-liquid phase, and ensure that the single crystal grows from the seed crystal position. The difficulty of this technique is to ensure that the seed crystal is not completely melted during the melting of silicon material. , and control the distribution of the temperature gradient, which is the key to improving the crystal growth rate and crystal quality. In order to meet the process requirements for the temperature gradient of the quasi-single crystal, it is necessary to open the damper when the furnace reaches 1450 degrees Celsius to gradually The cooling process and the thermal field with a suitable temperature distribution can not only ensure the smooth growth of single crystals, but also have high quality; the traditional design is to lift the steel cage of the furnace body to realize the heat dissipation of the furnace body. This heat dissipation method cannot meet the temperature requirements of quasi-single crystals. Gradient requirements are not conducive to the growth of single crystals, affecting the quality of single crystals, and when overflow occurs, it is easy to corrode the supporting structural parts, which brings great hidden dangers to the safety of the furnace

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