Method for preparing high-purity spraying-free coating at bottom of ingot casting single crystal

Abstract

The invention relates to a method for preparing a high-purity spraying-free coating at the bottom of an ingot casting single crystal. The method comprises the following steps: grinding fused quartz particles and deionized water in a ball mill, taking the resulting product out, adding the resulting product in a dispersion machine, adding silica sol, fused quartz powder, fused quartz powder and a high-purity ceramic binder, and stirring the mixture to form slurry A; adding fused quartz particles and deionized water into the ball mill for milling, taking the resulting product out, adding the resulting product into a stirrer, adding silica sol and fused quartz powder, and stirring the mixture to form slurry B; adding fused quartz particles and crystalline quartz in the ball mill for milling, taking the resulting product out, and mixing quartz slurry, silica sol, a binder and water to form slurry C; adding silicon nitride and deionized water to the stirrer, adding a silicon nitride sintering aid, silica sol and a high-purity binder, and fully stirring the mixture to form slurry D; and sequentially manufacturing a bottom lining flat layer, a rough loose layer, a quartz compact isolationlayer and a silicon nitride compact isolation layer. The method can effectively reduce a red area at the bottom of the ingot casting single crystal, and can reduce the proliferation of dislocation andother defects.

Description

technical field [0001] The invention relates to the field of crucible processing, in particular to a method for preparing a bottom high-purity spray-free coating for ingot single crystal. Background technique [0002] In the photovoltaic industry, in order to pursue the advantages of low cost, low energy consumption and large size of casting technology, and at the same time, in order to combine the high efficiency and high quality advantages of single crystal into the polycrystalline production process, in order to improve the production efficiency and Competitiveness, mostly using ingot single crystal technology. In ingot single crystal technology, a layer of high-purity isolation layer with a thickness of 0.5-1mm is made for the crucible body first, and silicon nitride coating is sprayed on the crucible before ingot casting. The silicon nitride coating is very loose and cannot Effectively block impurities in the crucible from entering the silicon ingot, resulting in a red...

AI Technical Summary

Problems solved by technology

[0003] 1. The red area at the bottom of cast single crystal is long, which reduces the yield of cast single crystal.

[0004] 2. Defects such as dislocations in cast monocrystalline silicon blocks proliferate rapidly;