Spray free crucible for low impurity cast polycrystal and ingot monocrystal and preparation method thereof

Abstract

The invention relates to a spray free crucible for low impurity cast polycrystal and ingot monocrystal and a preparation method thereof. The region, which is above a corresponding liquid level, of theinner surface of the matrix of the crucible is painted by a silicon nitride coating (I); and the region below a corresponding silicon liquid level and the bottom of the crucible are coated by a silicon nitride coating (II). The silicon nitride coating (I) has a four-layer structure. The basic layer is a hard enhanced silicon nitride coating; the middle is a buffer layer, and the surface is a hardprotective layer. Due to the buffer layer, the silicon liquid level region can well prevent the shrinkage of the crucible. The smooth hard layer on the surface can prevent the erosion of silicon liquid and ensures insulation strength. The middle buffer layer can reduce the influence of shrinkage of the crucible on the surface hard coating. The cracking of the surface coating is maximally reduced.The bottom matrix layer provides a good coating adhesion force. The provided silicon nitride hard coating technology can reduce the using amount of powdery basic materials, the content of impuritiesin silicon ingots, and defects in silicon ingots such as dislocations, greatly improves the de-moulding effect of silicon ingots, and avoids the phenomenon that silicon ingots are stuck on 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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