| Summary: | 碩士 === 國立臺灣大學 === 化學工程學研究所 === 105 === Silicon nitride is an alternative material to the widely used silica crucibles for silicon crystal growth, its advantages being the reusability in successive castings and much purier than quartz crucible and reduciton for a source for oxygen contamination of the ingot. Using reusable crucible for crystal growth are two advantages, firstly it reduces the cost for crystal growth, secondly the quality of the ingot is better than previous one. In this work, Using simple, lower cost and waste reduction method to make reusable silicon nitride crucible and the better method of crystal growth for reusable crucible. The most important thing is using recycled silicon rather than commercial silicon to make silicon nitride crucible is an better idea. It could reduce the waste in PV industry.
For recycled silicon crucible, adding 2wt% BaCO3 could enhance the level of nitridation of crucible effectively.But BaCO3 is not uniform in the greedbody. It can chager to use water solubility of Baric compound to solve this problem. However adding PMMA to increase the porosity of the crucible doesn’t work to the level of nitridation of crucible. It mean the main resistance of nitridation is not the nitrogen diffuse into the crucible pores. Add 5vol% of nitrogen into argon could prevent the decomposition of silicon nitride during crystal growth. Fired the silicon nitride crucible in Air at 1050℃ for 6h before every crystal growth could prevent infiltrate happen by Si melt.
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