Study on Functional Surface Formation by Liquid Cluster Ion Beams

团簇是由几十到几千个原子组成的集合体，构成了一种新的物质相，具有与固体、液体和气体明显不同的性质。它们是微小的粒子，处于原子状态和体状态之间的联系。团簇束是研究固体物理、化学和相关材料科学基础的有用工具。在本研究中，我们发展了一个液态团簇离子束系统，并利用绝热膨胀现象产生了酒精、水和石蜡等液态团簇。此外，我们还将液态团簇离子束技术应用于电子电气工程、光学机械工程和化学工程等各个工业领域，为了阐明液态团簇离子与固体表面如Si（100）、SiO_2和/或金属表面的相互作用，采用飞行时间和阻滞电位方法研究了液态团簇离子的溅射和清洗效应。物理和化学溅射，这是由液体团簇离子辐照增强，是不同的物种的团簇和衬底材料。例如，对于乙醇团簇离子束化学溅射Si表面，团簇中每个分子的能量是非常重要的，最佳能量范围在1 ~ 10 eV/molecule之间。对于Au表面的情况下，溅射的深度随着阻滞电压的增加而减小，并且物理溅射受团簇的最小尺寸的影响。因此，液体团簇与表面原子之间的表面反应动力学与传统湿法工艺显着不同。

A cluster is an aggregate of a few tens to several thousands of atoms, and constitutes a new phase of matter, with significantly different properties than solids, liquids and gases. They are tiny particles, which are in a position to a link between atomic state and bulk state. Cluster beams are useful tools for the investigation of the fundamentals of solid state physics, chemistry and related materials science. In this study, we have developed a liquid cluster ion beam system, and have produced liquid clusters such as alcohol, water and paraffin clusters by adiabatic expansion phenomenon. Furthermore, we have applied the liquid cluster ion beam technique to various industrial fields such as electric and electronic engineering, optical and mechanical engineering, and chemical engineering.In order to clarify the interactions of the liquid cluster ions with solid surfaces such as Si(100), Si0_2 and/or metal surfaces, sputtering and cleaning effects were investigated using the time-of-flight and the retarding potential methods. The physical and chemical sputtering, which was much enhanced by the liquid cluster ion irradiation, was different depending on the species of the cluster and the substrate materials. For example, for the chemical sputtering of the Si surfaces by the ethanol cluster ion beams, the energy per molecule in a cluster was of much importance, and the optimum energy range was between 1 eV/molecule and 10 eV/molecule. For the case of Au surfaces, the sputtered depth decreased with the increase of the retarding voltage, and the physical sputtering was influenced by the minimum size of the cluster. Thus, the surface reaction dynamics between the liquid clusters and the surface atoms were significantly different from that of conventional wet processes.