Method for forming coating on inner surface of polycrystalline silicon ingot casting crucible

Abstract

The invention relates to a method for forming a coating on the inner surface of a polycrystalline silicon ingot casting crucible, in particular to the method for forming the coating on the inner surface of the polycrystalline silicon ingot casting crucible without high-temperature sintering, and also relates to the polycrystalline silicon ingot casting crucible comprising the coating prepared by the method. Since a high-temperature sintering condition is not required in the method for forming the coating on the inner surface of the polycrystalline silicon ingot casting crucible, a large amount of energy can be saved; the effective weight ratio of the polycrystalline silicon cast ingot prepared by using the crucible is higher than that of the cast ingot prepared by the crucible prepared by using the conventional method, so that the production cost is reduced, and the production efficiency is increased.

Description

technical field [0001] The present invention relates to a method for forming a coating on the inner surface of a crucible for polysilicon ingot, especially a method for forming a coating on the inner surface of a crucible for polysilicon ingot without high temperature sintering. The invention also relates to a crucible for a polysilicon ingot comprising a coating formed using the method. Background technique [0002] The basic materials of crystalline silicon solar cells are polycrystalline silicon wafers and monocrystalline silicon wafers. Polycrystalline silicon wafers are cut from polycrystalline silicon ingots produced by directional solidification. The polysilicon directional solidification method is to melt the polysilicon raw material in a quartz crucible, and control the temperature gradient of the melt to solidify the silicon melt from bottom to top to obtain a polysilicon ingot with upward grain growth. [0003] The main component of the quartz crucible used for p...

AI Technical Summary

Problems solved by technology

[0005] However, there are still some problems with silicon nitride coatings in the prior art: 1) silicon nitride coatings are all formed by high temperature sintering, which makes energy consumption relatively high; 2) silicon nitride coatings are generally sprayed The method prepares silicon nitride powder into a coating, and the coating density is low, and it is easy to fall off before or during use; 3) The thickness of the silicon nitride coating in the prior art is generally required to be more than 200-300 microns , and uniform everywhere, in fact, the requirements for the coating are not the same everywhere in the quartz crucible, especially the erosion of the coating at the liquid level of the silicon melt is more serious, so the thickness of the coating also needs to be optimized

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