A kind of preparation method of low-oxygen quartz crucible

Abstract

The invention provides a method for preparing a low-oxygen quartz crucible, comprising the following steps: S1: preparing a high-purity quartz sand coating on the surface of the crucible, and the high-purity quartz sand contains SO 2 Mass fraction ≥ 99.999%; S2: Prepare a silicon nitride coating on the surface of the high-purity quartz sand coating. The high-purity quartz sand coating prepared by the present invention improves its water absorption characteristics; in addition, the present invention uses alcohol-based silica sol to prepare a silicon nitride coating, which enhances the bonding force between the high-purity quartz coating and the silicon nitride coating, A denser silicon nitride coating is obtained to reduce the infiltration of oxygen in the crucible to the silicon ingot.

Description

technical field [0001] The invention belongs to the technical field of preparing a crucible for polycrystalline silicon ingots, and in particular relates to a method for preparing a low-oxygen quartz crucible. Background technique [0002] At present, the preparation method of polycrystalline silicon ingots is mainly carried out by using the directional solidification system provided by GT Solar, which usually includes steps such as heating, melting, crystal growth, annealing and cooling. During the solidification and crystal growth process, the temperature of the top and the opening of the side insulation cover are controlled so that the molten silicon liquid can obtain sufficient supercooling at the bottom of the crucible to solidify and crystallize. At present, the oxygen content in the conventional polycrystalline ingot process ranges from 10-16ppm, although it can meet the requirements of conventional battery technology, but with the popularization of passivated emitter...

AI Technical Summary

Problems solved by technology

At present, the oxygen content in the conventional process of polycrystalline ingots ranges from 10-16ppm, which can meet the requirements of conventional battery technology, but with the popularization of passivated emitter and rear cell technology (that is, Passivated Emitter and Rear Cell, abbreviated as PERC), The silicon dioxide introduced in the preparation process of the prior art has a high oxygen content, so the sprayed coating obtained has a high oxygen content and poor compactness. During the subsequent ingot casting process, the oxygen in the sprayed coating diffuses into the silicon ingot, resulting in The oxygen content in the silicon ingot reduces the light decay effect of the cell

However, the light attenuation problem caused by the high oxygen content of the ingot increasingly does not meet the development needs of existing high-efficiency batteries, and does not meet the needs of grid parity for photovoltaics.