冷坩埚定向凝固太阳能级多晶硅的熔铸机理与硅锭结构特征

项目名称： 冷坩埚定向凝固太阳能级多晶硅的熔铸机理与硅锭结构特征

项目编号： No.50804012

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 陈瑞润

作者单位： 哈尔滨工业大学

项目金额： 19万元

中文摘要： 通过制备新型冷坩埚和新型硅颗粒加料器，真空中冷坩埚定向凝固太阳能级多晶硅过程和硅锭组织结构为研究对象，研究坩埚内电磁场特征，系统研究冷坩埚定向凝固太阳能级硅实验中的加热启动方式，感应线圈形状、位置和匝数，原硅料的颗粒尺寸、加入量和加入速度，电源参数等相关因素对熔化质量和凝固组织的影响机理；在不同条件下制备各种的硅锭，系统研究冷坩埚定向凝固多晶硅过程中的加热启动、硅熔化机理、熔体驼峰形成和特征；研究在连续铸造过程中的熔化波形为，凝壳形成机制，定向凝固行为，获得冷坩埚定向凝固顺利进行的理论判据。获得工艺参数对宏观组织围观组织影响规律。研究硅锭中杂质、晶体缺陷分布特征及与凝固过程的相关性。测试了具有定向凝固组织的硅锭电阻率、少子寿命、间隙氧和间隙碳含量，发现经过定向后，这些性能都得到提高。

中文关键词： 冷坩埚；太阳能级多晶硅；连续铸造；定向凝固

英文摘要： In this study, a new type electromagnetic cold crucible and a new feeding system were designed and fabricated. The structure of the silicon ingot and the processing of cold crucible directional solidification were investigated. The characteristic of the electromagnetic field were revealed. The effect of start-up, the shape, the position and the turned of the induction coil, the granular size, the feeding volume and velocity on the melting quality and solidification structure were researched. The silicon ingots were prepared under different conditions. The mechanism of the melting, the meniscus froming and heating style were studied. The melting wave, the forming of the skull, the solidificaiton ways were researched and the criterion of cold crucible directional solidification was obtained. Effect of experimental parameters on the macrostructrue and microstructure were deduced. The impurities, the crystalline defects in the solicon ingtos were studied. The electrical resistivity, minority carrier lifetime, the interstitial oxygen and carbon were measured, these properties were improved.

英文关键词： cold crucible;solar grade crystalline silicon;continuous casting;directional solidification