铬天青S光度法及非线性拟合测定高纯硅中微量铝  

Determination of Trace Aluminum in High-purity Silicon with Chrome Azurol S Spectrophotometry by Nonlinear Fitting

作　　者：傅翠梨[1] 卢成浩[1] 张蓉[1] 黄平平[1] 吴浩[1] 罗学涛[1] 李锦堂[1] 

机构地区：[1]厦门大学材料学院,福建厦门361005

出　　处：《岩矿测试》2012年第1期132-137,共6页Rock and Mineral Analysis

基　　金：福建省自然科学基金项目(2010J05120)

摘　　要：铬天青S光度法是硅中铝含量的测定方法之一,该方法的标准曲线大多采用不过零点的线性拟合,导致低铝含量测定误差大。为提高方法准确度并降低方法检出限,研究了铝标准曲线低浓度部分的拟合问题,探讨了不同拟合模型对检测结果准确度的影响。实验结果表明,不同浓度铝标准液的吸光度在0～0.3μg/mL范围内并不满足一次函数线性关系,采用三次函数关系y=-17.45230x3+10.42883x2+1.04047x(y为扣空白的吸光度,x为铝的质量浓度)拟合能获得良好结果,其相关系数R2为0.99975。利用已知铝含量的硅试液检验该公式,其相对标准偏差(RSD)为2.55%。样品中铝的测定值与电感耦合等离子体发射光谱法测定值吻合。该法可以显著提高低浓度的铝测定的准确性,可用于测定高纯硅中含量在0.55μg/g以上的铝杂质。Spectrophotometry with chrome azurol S is one of the methods used to determine aluminum content in silicon. Since the standard curve is linear but does not pass through the origin, it leads to a large measurement error with low aluminum content. In order to improve the accuracy and decrease the detection limit, the spectrophotometric aluminum standard curve was analyzed in the low A1 content part and the effect of different models on the data accuracy is discussed in this paper. Results indicate the absorbanee of aluminum standard solution at 0 - 0.3μg/mL did not match with the linear relation, while the function of y = 17. 45230x3 ＋ 10. 42883 2 x ＋ 1. 04047x （y for absorbance deduct blank, x for aluminum concentration） yielded good results where R2 reached 0. 99975. This formula was evaluated by the certified aluminum content in different volume polysilicon solutions. The relative standard deviation is 2.55%. The result matches the one obtained by the inductively coupled plasma atomic emission spectroscopy method. This method can improve the measurement accuracy of low content aluminum in polysilicon when the content of aluminum is greater than 0.55 μg/g.

关 键 词：高纯硅 铝 铬天青S光度法 标准曲线 函数拟合 

分 类 号：O657.32[理学—分析化学] O613.72[理学—化学]