铸锭多晶硅片晶体质量差异性研究

STUDY ON THE QUALITY DIFFERENCE OF CASTING MULTICRYSTALLINE SILICON WAFER

以铸锭多晶硅片具有质量差异性的区域为研究对象,综合分析其杂质浓度、位错密度和少子寿命间的关系。结果表明:当位错密度相近时,高浓度的金属杂质会引起少子寿命的大幅降低;而当金属杂质浓度相近时,位错浓度的升高也会引起少子寿命的降低。金属杂质和位错等微缺陷作为电活性中心极大地制约了铸锭多晶硅晶体质量的提高,必须通过工艺的改善加以消除。

This paper focuses on the selected area with different crystal quality in casting muhicrystalline silicon wafer. The relationship of impurity concentration, dislocation density, and minority carrier lifetime was systemically discussed. The results revealed that when the dislocation density is close, the minority carrier lifetime is dramatical- ly decreased with high metal impurity concentration. When the metal impurity concentration is close, the minority carrier lifetime is variable with the dislocation density. The crystal quality of silicon is greatly restricted by the microdefects of metal impurity and dislocation, working as electroactive centers. Then, such microdefeets should be diminished to improve the crystal quality.