报告题目(中文):Cu/Si晶界系统中的扩散系数的LEIS研究
报告题目(英文):Diffusion coefficient measurement by LEIS in Cu/Si grain boundary systems
报告内容简介:
Surface islands formed by grain-boundary diffusion has been studied in Cu/Si and Ni/Cu nanolayers by in-situ low energy ion scattering spectroscopy (LEIS), X-ray photoelectron spectroscopy (XPS), scanning probe microscopy (STM) and ex-situ depth profiling based on secondary neutral mass spectrometry (SNMS). A new experimental approach of the measurement of grain boundary diffusion coefficients is presented. It is based on appearing time measurement of silicone atoms diffused through a few nanometers thick copper layer and detected by surface sensitive LEIS method. The temperature range of 423–463 K insures the pure C-type diffusion kinetic regime. Grain boundary diffusion coefficients were estimated by the relation used for calculation of diffusant distribution from a constant source in assumption that the diffusion path equals to the film thickness at the moment of appearing Si atoms on the Cu surface. At 453 K we estimated the surface segregation factor and detected formation of Cu–O–Si atomic bonds on the Cu film surface measured by XPS. Depth distribution of Cu in Ni layer has been determined by SNMS depth profile analysis. A combined measurement technique of LEIS and SNMS gave a unique possibility to measure the fast diffusion in nanolayers at low temperatures. Furthermore, the advantage of this technique was that determination of grain boundary diffusion coefficient did not require a complicated calculation with segregation factors in order to remove the effect of B-type diffusion kinetic and, as a result of this, the diffusivity could be studied in a simply way, only by measurement of the appearing time.
采用原位低能离子散射光谱(LEIS)、X射线光电子能谱(XPS)、扫描探针显微镜(STM)和非原位基于二次中性质谱(SNMS)的深度分析方法,研究了Cu/Si和Ni/Cu纳米层中晶界扩散形成的表面岛。提出了一种测量晶界扩散系数的新实验方法。它是基于硅原子在几个纳米厚的铜层中扩散的出现时间测量,并用表面灵敏的LEIS方法进行检测。在423–463 K温度范围内确保了纯C型扩散动力学状态。晶界扩散系数是通过用于计算来自恒定源的扩散剂分布的关系来估计的,假设扩散路径等于在Cu表面上出现Si原子时的膜厚度。在453 K时,我们估计了表面偏析因子,并通过XPS检测到Cu膜表面形成了Cu–O–Si原子键。通过SNMS深度剖面分析,确定了Cu在Ni层中的深度分布。LEIS和SNMS的组合测量技术为测量低温下纳米层中的快速扩散提供了独特的可能性。此外,该技术的优点是,晶界扩散系数的确定不需要使用偏析因子进行复杂的计算,以消除B型扩散动力学的影响,因此,可以通过测量出现时间以简单的方式研究扩散率。
报告人姓名:Viktor TAKÁTS
报告人简介(中文):Viktor TAKÁTS,研究员,博士生导师。TAKÁTS研究员所在的匈牙利科学院核研究所拥有表面物理和薄膜物理领域的工作经验和实验技术,能够在亚纳米尺度上提供高水平的研究工作。同时获得的元素的深度浓度和化学状态可以使人们对物质性质有新的认识,这是任何其他方法都无法实现的。TAKÁTS研究员长期从事表面物理和薄膜物理的研究工作,已发表本领域45篇SCI论文,参与1本著作,获得授权专利1项,获得4个项目基金的资助。TAKÁTS研究员主要负责一个SNMS-XPS-LEIS-SPM集成系统,该集成系统属于世界领先的分析测量系统,包括:
-低能离子散射光谱(LEIS,low-energy ions scattering spectroscopy,LEIS)技术方法可以得到最顶层一个原子层的信息;
-XPS(X射线光电子能谱)能给出样品表面的定量和定性信息,从而描述化学环境和元素组成。在XPS中,信号来自被分析区域的上部原子层,表面深度为3-10nm;
-二次中性质谱仪(SNMS)用于纳米级深度剖面分析;
-扫描探针显微镜(SPM)在超高压下工作可以产生原子分辨率的高分辨率图像。
报告人单位(中文):匈牙利核研究所
报告人单位(英文):Institute for Nuclear Research, Hungary
报告时间:2023年9月28日 上午 10:00
报告地点:宝山校区东区材料楼B楼520报告厅
主办单位:bg大游官网官方平台bg大游官网官方平台
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