Charging method for sunken monocrystalline silicon-like seed crystal melting control

Abstract

The invention discloses a charging method for sunken monocrystalline silicon-like seed crystal melting control. The charging method comprises the following steps that silicon nitride powder is sprayed onto the inner surface of a quartz crucible to serve as a protective layer after cooling; a layer of rapeseed material is laid at the bottom of the quartz crucible; seed crystal plates or seed crystal blocks are laid on the rapeseed material to serve as a seed crystal layer for a directional coagulating-casting semi-melting process; gaps among the laid seed crystal plates or seed crystal blocks are fully filled with a small-particle protogenetic polycrystalline silicon material; a rapeseed material is laid on the seed crystal layer to serve as a buffer layer; crystal bricks are laid on the buffer layer to serve as a blocking layer, and the crystal bricks of the blocking layer are gradually lowered from a crucible wall to the center of the crucible to form a sunken structure; a silicon material is stacked on the blocking layer in a layer-by-layer mode till the silicon material requirement is met. The charging method has the advantages that the molten silicon material flows towards the center of the crucible at sunken angles of the crystal bricks when flowing from the top to the bottom to pass through the blocking layer. Therefore, the phenomena that the lateral seed crystal layers are molten through and the seed crystal layer at the central position is not molten can be avoided.

Description

technical field [0001] The invention belongs to the field of polysilicon melting, and relates to a charging method for controlled melting of a sunken monocrystalline silicon seed crystal. Background technique [0002] The equipment and ingot principle used in the quasi-single crystal ingot are the same as those of the polycrystalline silicon ingot. However, since the quasi-single crystal ingot needs to form a large single crystal silicon ingot, and polycrystalline silicon does not need to form a large single crystal grain, so , There are certain differences between the quasi-single crystal ingot casting process and the polycrystalline silicon ingot. For example, it is necessary to consider the influence of the melting state of the seed layer on the growth of the quasi-single crystal silicon ingot. [0003] During the melting process, the solid-liquid interface of the single crystal moves from top to bottom, melting the silicon material. In the melting process of polycrystal...

AI Technical Summary

Problems solved by technology

[0002] The equipment and ingot principle used in the quasi-single crystal ingot are the same as those of the polycrystalline silicon ingot. However, since the quasi-single crystal ingot needs to form a large single crystal silicon ingot, and polycrystalline silicon does not need to form a large ...

Images