Real Time Sputter Depth Measurement for In Situ Surface Microanalysis

用二次离子质谱法（西姆斯）和俄歇电子光谱法对固体表面的元素组成进行深度分布分析需要从表面离子束溅射材料以产生深度增加的凹坑。只有在测量完成后，才能通过轮廓测量法测量弹坑深度，计算溅射速率的平均值，并完成成分与深度的校准。不幸的是，溅射速率在不同的材料中可以有很大的差异，这会改变界面的表观位置。溅射速率也与离子产率有关，离子产率影响用于定量西姆斯中杂质数据的相对灵敏度因子。随着工业对空间和成分精度的要求越来越高，以及对更快的分析周转的要求越来越高，原位和真实的实时测量弹坑深度和溅射速率非常重要。干涉法是这种测量的理想工具，因为它是精确的和非接触的Charles Evans Associates建议开发一种工具，适用于现有的分析仪器，提供动态深度测量，分辨率接近1纳米。要做到这一点，必须解决这个独特应用程序特有的几个问题。在第一阶段，研究人员将建立一个示范干涉仪受现场应用的限制。他们将进行实验，以评估深度分辨率，并研究各种材料和近地表结构的影响。在第二阶段，将设计将该装置纳入现有的分析仪器。

Depth profile analysis of elemental composition at solid surfaces with secondary ion mass spectrometry (SIMS) and Auger electron spectrometry requires ion beam sputtering of material from the surface to create a crater of increasing depth. Only after the measurement is completed can the crater depth be measured by profilometry, the sputter rate averaged, and the calibration of composition versus depth completed. Unfortunately, sputter rates can vary widely in different materials, which shifts the apparent position of interfaces. Sputter rate has also been linked to ion yield, which affects the relative sensitivity factors used to quantify impurity data in SIMS. As industrial demands increase for higher levels of spatial and compositional accuracy, and for faster analytical turn around, it is important to measure crater depth and sputter rate in situ and in real time. Interferometry is an ideal tool for this type of measurement since it is precise and non-contacting Charles Evans & Associates proposes to develop a tool, adaptable to existing analytical instruments, that provides dynamic depth measurements to a resolution approaching one nanometer. To do this, several issues specific to this unique application must be addressed. During Phase I the researchers will build a demonstration interferometer subject to the constraints of in situ application. They will perform experiments to assess depth resolution and to study the influence of various materials and near-surface structures. A design will be laid out for incorporating this device into an existing analytical instrument in Phase II.