A spray-free crucible for cast polycrystal and ingot single crystal with low impurity and its preparation method

Abstract

A low-impurity spray-free crucible for casting polycrystalline and ingot single crystal and its preparation method, the inner surface of the substrate is coated with silicon nitride coating I on the area above the liquid line corresponding to the area below the silicon liquid line and the bottom of the crucible Coated with silicon nitride coating II. Silicon nitride coating I has a four-layer structure, the base layer is a hardened silicon nitride coating, the middle is a buffer layer, and the surface is a hard protective layer. The presence of the buffer layer enables the silicon liquid line region to better resist the shrinkage of the crucible. The smooth surface hard layer can provide the ability to resist the erosion of silicon liquid and ensure the insulation strength. The middle buffer layer can reduce the impact of crucible shrinkage on the surface hard coating and minimize the cracking of the surface coating. The bottom substrate layer provides a good Coating adhesion. The present invention focuses on the silicon nitride coating hard technology, so as to realize less foundation materials, reduce the impurity content of silicon ingots and reduce defects such as silicon ingot dislocations, greatly improve the demoulding effect of silicon ingots, and reduce the phenomenon of silicon ingots sticking to the crucible .

Description

technical field [0001] The invention relates to a crucible production technology, in particular to a low-impurity spray-free crucible for casting polycrystals and ingot single crystals and a preparation method thereof. Background technique [0002] In the prior art, a layer of silicon nitride coating is pre-painted on the silicon liquid line of the crucible, and then sprayed. Such technical processes have a certain range of applications in the market. This type of technology is helpful to reduce stickiness, but since the post-production coating is also sprayed with silicon nitride, and the coating is also particle stacking, there will also be powder particles peeling off during use, resulting in the impurity content of silicon ingots. increased situation. [0003] For example, the patent application with the application number: 201610932533.2 "A Method for Preparing a Silicon Nitride Coating for Polysilicon Ingots" also uses a pre-painted silicon nitride coating, and then ...

AI Technical Summary

Problems solved by technology

However, on the one hand, considering the oxygen content of the silicon ingot, the amount of silica sol is usually not suitable for a large amount of introduction, so the normal temperature strength of the coating is very limited.

Furthermore, in the existing mainstream spraying process, the coating obtained by loose particle stacking is also difficult to improve the hardness of the coating

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