用于实时溅射深度测量的新型Grimm辉光放电光源的设计

摘要

采用辉光放电光谱仪进行物质表面深度分析时,样品溅射深度是重要的分析信息.本文设计了一种新型Grimm辉光放电光源,此光源与激光位移测距传感器构成的测昔系统可对样品溅射深度进行实时测量,并保证了良好的辉光溅射效果和分辨多层结构及界面的能力.采用激光三角测量技术,在辉光光谱分析的同时对溅射深度进行实时测量,能够有效地解决传统深度分析方法中步骤繁琐以及对深度估算不准确等问题.本光源采用光纤将辉光光谱信号从光源传至多道分光光电检测系统,在结构上首次实现了元素光谱信号和溅射深度信号的实时采集及基于时间的同步分析,对标准样品得到了理想的实时溅射深度测量曲线.本文详细介绍了此新型辉光放电光源的设计思路和工作原理.本辉光放电光源具有良好的深度分辨率,在30 mA,900 V,20 min的溅射条件下,对铁基和铜基样品的溅射速率分别约为10和55 nm·s-1,文中给出了样品的溅射坑表面形貌图和溅射坑显微照片.对中低合金钢标准样品进行了分析精密度实验,分析精度良好,其中C,Cu,Al,Ni,Mo,Mn,V元素相对标准偏差(RSD)均小于1.7%.Cr和Si元素RSD小于2.6%,给出了实测数据.%The crater depth value of sample surface during sputtering is important analysis information for the depth profile analysis of glow discharge spectrometry. Real-time sputtered depth measurement with Laser triangulation measurement method for glow discharge compositional analysis, effectively solves the issues of incorrect depth value calculation and complicated procedures in traditional depth analysis method. This paper presents a new Grimm-type glow discharge source for real-time sputtering depth measurement by laser displacement sensor. This GD source also ensures fine sputtering effects and ideal resolution for multi-layer structure and interface. Optical fiber is used to transmit glow spectrum signal from GD-source to multi-channel photoelectric detection system. The design for the first time accomplishes the real-time signal collection and time-based synchronization analysis for both spectrum signal and sputtering depth signal. The real-time sputtering depth measurement curve of standard samples is obtained. The design and operating principle of this new-type GD-source is described in detail. Under the sputtering conditions of 30 mA, 900 V and 20 minutes, the sputtering rates of iron-based and copper-based sample sputtered by this GD source with good depth resolution are about 10 and 55 nm · s-1. Surface topography picture of sputtering crater and microphotograph of metal samples are provided in the paper. Low-alloy steel standard sample is tested with this new GD source, the relative standard deviation (RSD) of C, Cu, Al, Ni, Mo, Mn and V elements are less than 1. 7％,while for Cr and Si elements RSDs are less than 2. 6 ％. The result data of the testing is provided in this paper.