193 nm ArF准分子激光剥蚀系统高空间分辨率下元素分馏研究

Elemental Fractionation Studies of 193 nm ArF Excimer Laser Ablation System at High Space Resolution Mode

研究了193 nm ArF准分子激光剥蚀系统高空间分辨率下的仪器检出限、ICP质量负载元素分馏、剥蚀深度/束斑直径元素分馏以及基体效应,并在10μm束斑直径下分析了GSD-1G、StHs6/80-G和NIST612中的微量元素。结果表明,仪器检出限随束斑直径的减小而升高,当束斑直径降低至7μm时,部分微量元素的仪器检出限为1-10μg/g。ICP质量负载元素分馏指数与元素第一电离能呈正相关和元素氧化物熔点呈负相关。当剥蚀深度与束斑直径比小于1∶1时,由剥蚀深度/束斑直径引起的元素分馏效应可以忽略不计。基体效应研究表明,50μm与10μm激光束斑下基体效应没有明显的差别。以NIST610为校准物质,Ca为内标元素,10μm束斑直径下GSD-1G、StHs6/80-G和NIST612中的36种微量元素分析结果与定值基本吻合,分析结果与定值基本匹配。综合考虑在10μm的空间分辨率下,该技术可满足准确分析微量元素的要求。

Limits of detection （ LODs）, ICP mass load effect, downhole induced fractionation and matrix effect of 193 nm ArF excimer laser ablation system at high spatial resolution were systematically investigated. Trace elements in GSD-1 G, StHs6/80-G and NIST612 were analyzed at 10μm spot size. The results showed that LODs decreased with increasing ablation diameter. LODs of some trace elements were in a range of 1- 10μg/g at 7 μm spot size. Mass load effect was negatively correlated with corresponding oxide melting temperature, while positively correlated with elemental 1^st ionization potential. Downhole fractionation was negligible when the ratio of ablation depth versus spot size was smaller than 1： 1. Matrix effect based on elemental pair method showed that there was no significant change between spot sizes of 50 μm and 10 μm among investigated reference materials （NIST610, GSD-1G, ATHO-G and StHs6/80-G）. Based on NIST610 as external standard and Ca as internal standard, the analytical results of 36 trace elements in GSD-1G, StHs6/80-G and NIST612 at 10μm spot size matched well with the reference value. In general, 10 μm spatial resolution could satisfy the requirements of trace element analysis.