为了发展一种实时、快速、非接触,能对金属氧化物纳米薄膜中元素成分进行分析的检测方法,搭建了一套基于LIBS技术的薄膜检测分析系统.该系统可同时实现样品平面的精确定位,样品烧蚀坑形貌实时观测,等离子体成像和光谱采集等功能.样品为在单晶硅基底上利用溶胶-凝胶法制备的约40 nm厚的氧化锆功能薄膜,实验中将其放置在一个位移精度为0.01 mm的三维平移台上.系统测试结果表明,在两束聚焦的连续激光辅助下,样品平面的定位精度达到了20 μm,LIBS单脉冲检测光谱信号的面积分强度的重复性的相对标准偏差(RSD)达到了1.6%.在室温和大气环境下,对等离子体空间分布、信号强度随激发能量、时间参数和LTSD(激光聚焦点到样品表面的距离)参数而变化的情况从光谱角度进行了实验研究,并优化了实验参数和探测参数.利用实验得到的光谱数据,用玻尔兹曼方计算了等离子体的电子温度,利用硅的原子线计算了电子密度,对定量检测所必须的局部热力学平衡(LTE)条件进行了评价.

In order to develop a method to analyze the metal elements in the thin film samples rapidly,directly and without sample preparation,a laboratory LIBS system was established recently for nanometer film analysis.This system could determine the position of sample plane,observe the profiles of sample after pulse-material interaction and detect the plasma morphologyand spectral emission at the same time.Samplesused were ZrO2 films about 40 nm thickness prepared on Si by a sol-gel process,and they were located on a manual X-Y-Z translational stage with theaccuracy of 0.01 mm.Final results showed that the positional accuracy is about 20μm with the help of two CW lasers,and the RSD of repeatability of single-shot spectra could be to 1.6%.We investigated special morphology of plasma,variation tendency of signal intensity as a function of pulse energy,LTSD(laser focus to sample distance) and time,which provide cornerstone for optimizing experimental parameters under the conditions of room temperature and atmospheric pressure.We calculated plasma temperature by way of Boltzmann curve and electron densitythrough the acquired data.We also appraised necessary LTE conditions for quantitativeanalysis.