Crucible and coating method thereof

Abstract

The invention discloses a crucible and a coating method of the crucible. The disclosed coating method of the crucible comprises the following steps: coating paint is manufactured, and the coating paint comprises hexagonal boron nitride and pure water; the coating paint is coated on the inner wall of the crucible in a spraying mode; and the crucible is aired to be dry. The possibility of the reaction between the crucible and the hexagonal boron nitride is small, silicone material is not prone to stick to the crucible, the possibility of occurrence of leakage is obviously lowered, and therefore the safety and reliability in the process of production of the silicone material are improved. Meanwhile, a coating is poor in wettability with liquid silicone and is not prone to stick to the silicone materials under the condition of carrying the liquid silicone. In addition, due to the fact that the hexagonal boron nitride has good wettability, demolding of a silicone ingot is good. The coating enables the heat conduction to be more uniform in the growth process of the silicone ingot, so that the interior quality of the silicone ingot is improved. Therefore, the coating method of the crucible is capable of reducing the sticking and permeation between the crucible and the liquid silicone material, plays a role in a protective layer, has the functions of lubrication and demolding, and improves the production quality of the silicone material and production efficiency.

Description

technical field [0001] The invention relates to the technical field of silicon material production, in particular to a crucible for producing silicon material. Furthermore, the invention also relates to a coating method applied to such a crucible. Background technique [0002] In the fields of photovoltaic solar energy and semiconductors, the most widely used semiconductor material is monocrystalline silicon / polycrystalline silicon. The preparation method of single / polycrystalline silicon material is by putting raw silicon material into a crucible system, and the crucible generally uses a quartz ceramic crucible, and its main component is silicon dioxide. The raw silicon material is first melted into a liquid state in the crucible, and then directional cooling grows single / polycrystalline silicon that meets the requirements. The current industry trend is to produce products with larger sizes, which will increase the production cycle. Liquid silicon materials need to be in ...

AI Technical Summary

Problems solved by technology

[0012] A. The main component of silicon nitride used in the prior art at room temperature is α-Si 3 N 4 , will undergo a phase transition at a temperature of about 1300 ° C to generate β-Si 3 N 4 , the above changes cause instability inside the coating, affect the quality of the coating, and increase the possibility of silicon material sticking to the pot or even leaking;

[0013] B. Although the silicon nitride coating itself has a certain high temperature resistance, its thermal conductivity is poor. With the advancement of technology, it is the development trend of the industry to use silicon materials with stronger thermal conductivity, which can be significantly improved. The uniformity of heating, so the low thermal conductivity of the crucible and coating material cannot be well adapted to the production needs;

[0014] C. Silicon nitride has a close-packed hexagonal structure, which leads to its high hardness, and the silicon nitride coating is relatively dense, so the demoulding effect is not ideal; and it is easy to wet with molten silicon, making the silicon material bonded to the coating Especially in the field of ingot casting, it will have a great impact on the growth of polycrystalline silicon ingots, and it is easy to cause cracks around the silicon ingots due to adhesion with the crucible coating;

[0015] D. The existing technology needs to bake the sprayed coating once, which is time-consuming and labor-intensive, which makes the use efficiency of the crucible not high and indirectly affects the production efficiency of the silicon block.

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