可回用坩堝的多晶矽生長之研究

Growth of Mutli-crystalline Silicon Ingot by Using Reusable Crucible

藍健宇(Chien-Yu Lan)

指導教授 ： 藍崇文

國立臺灣大學/工學院/化學工程學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201703236

摘要

氮化矽是一種有潛力替代目前業界長晶用的石英坩堝的材料，而使用氮化矽坩堝長晶主要優勢在於坩堝的可回用性，純度較高及得到低氧含量的晶碇，而且當使用坩堝重複長晶時，有兩個優點，第一可以減少長晶成本，第二可以得到品質更佳的晶碇。本論文提出簡單、低成本且可減少廢棄物的可回收氮化矽坩堝製作及提高坩堝回收次數的長晶的方式，同時較一般文獻不同的是，使用回收矽而非一般商業用矽粉當製作坩堝的材料能減少廢棄物產生，落實永續經濟於太陽能產業。

對於回收矽坩堝，添加2wt%碳酸鋇於坩堝中能有效的提升坩堝的氮化程度。可是初步觀察到碳酸鋇有分布不均的問題，而必須改使用水溶性的鋇化合物，讓鋇以離子的形態存在來改善分布不均的問題；而坩堝內添加2um的PMMA製造多孔性並無顯著提升氮化程度的效果，表示氮化主要的阻力並非是氮氣於坩堝孔洞內的擴散。長晶時添加5vol%的氮氣於氬氣氣氛中，可有效的避免氮化矽於高溫下被裂解的現象，以提高坩堝回用的次數，且每次長晶前將坩堝在空氣下1050℃持溫6小時氧化後即可重複使用坩堝長晶。

關鍵字

氮化矽 ； 可回用性 ； 碳酸鋇 ； 氮化程度 ； 氮化矽裂解 ； 回收矽

並列摘要

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.

並列關鍵字

Silicon nitride ； reusable ； BaCO3 ； level of nitridation ； decomposition of silicon nitride ； recycled silicon

參考文獻

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