直流辉光放电质谱法测定多晶硅中关键杂质元素的相对灵敏度因子

采用直流辉光放电质谱(dc-GD-MS)测定多晶硅中关键杂质元素的相对灵敏度因子(RSF).标样制作过程中主要是在连续通入氩气条件下将固定量的非标准多晶硅样品熔化,向硅熔体中均匀掺入浓度范围为1～30 μg/g的关键杂质元素(如B和P),采用快速固化法制成标样；再将制成的标准样品加工成一系列适合GD-MS扁平池(Flat Cell)的片状样品(20 mm×20 mm×2mm).采用二次离子质谱法(SI-MS)对标准样品中关键掺杂元素进行多次定量测定,取平均值作为关键杂质元素的精确含量.优化一系列质谱条件后,运用GD-MS对标样中关键掺杂元素的离子强度进行多次测定,计算平均结果,得到未校正的表观浓度,利用标准曲线法计算出关键杂质元素的相对灵敏度因子.

Determination of Relative Sensitivity Factors of Impurities in Poly-Silicon by Derect Current Glow Discharge Mass Spectrometry

This paper mainly describes the determination of relative sensitivity factors(RSF) of the key impurities in poly-silicon by direct current glow discharge mass spectrometry(dc-GD-MS).Appropriate content of non-standard poly-silicon samples was molten in furnace under argon atmosphere and cast to ingot.Prior to casting,the B and P key impurities were added to the silicon melt in the range of 1-30 μg/g.Then a series of standard samples were made for the flat cell analysis(20 mm×20 mm×2 mm).The accurate concentrations of the key impurity in these standard samples were determined by secondary ion mass spectrometry(SI-MS) analysis.The key impurities of standard samples were also detected by GD-MS to get the ion intensity and the uncorrected concentration under optimized conditions.The relative sensitivity factors(RSF) of key impurities were calculated by the experimental formula and standard curve method.