Silicon nitride solution and preparation method, and polysilicon ingot casting crucible and making method thereof

Abstract

The invention provides a silicon nitride solution and a preparation method thereof. The preparation method of the silicon nitride solution comprises a step of mixing silicon nitride powder with deionized water, a step of adding hydrochloric acid, and a step of stirring to obtain the silicon nitride solution. The invention also provides a polysilicon ingot casting crucible and a making method thereof. The making method of the polysilicon ingot casting crucible comprises a step of heating a crucible body, and a step of spraying the silicon nitride solution onto the surface of the inner wall of the crucible body to obtain the polysilicon ingot casting crucible. Hydrochloric acid diminishes the pH value of the silicon nitride solution and makes a Zeta potential approach zero, so the intergranular static repulsion force is reduced, the agglomeration effect is enhanced, and agglomeration is easy, thereby the bonding strength between the silicon nitride solution and the crucible is increased, and a problem of crucible stickiness caused by coat shredding is avoided.

Description

technical field [0001] The invention relates to the technical field of polysilicon ingot production, in particular to a silicon nitride solution and a preparation method thereof, a crucible for polysilicon ingots and a preparation method thereof. Background technique [0002] The polysilicon ingot industry is mainly divided into three links: crucible spraying, crucible charging and ingot casting. The whole process of ingot casting is divided into heating, melting, growth, degradation and cooling. During the heating process, the bulk silicon material reaches the melting point after heating to form liquid silicon, and the main material of the crucible is silicon dioxide. The chemical reaction of silicon oxide will cause the sticky crucible to make demoulding difficult, and in severe cases, it will cause the crucible to rupture and cause silicon leakage, resulting in economic losses and safety accidents. Therefore, it is necessary to spray a layer of silicon nitride coating on...

AI Technical Summary

Problems solved by technology

[0004] However, the inner wall of the crucible is smooth, which will cause the coating to fall off during the process of spraying silicon nitride, resulting in spraying failure. Even if the spraying is successful, the coating will fall off and the silicon ingot will stick to the crucible due to the influence of temperature and environment during the charging process or ingot casting process.