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Methodological Development of Large Cluster Ion Generation by Swift-Heavy-Ion-Induced Electronic Sputtering

快重离子诱导电子溅射产生大团簇离子的方法进展

基本信息

批准号：
13558061
负责人：
IMANISHI Nobutsugu
金额：
$ 7.1万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

We previously found that large cluster ions are emitted with extraordinarily high sputtering yields in an electronic-collision-dominant velocity range. Energy distribution of these cluster ions is very narrow compared to those emitted through the linear collision cascade process in a nuclear-collision-dominant velocity range. The aim of the present study is to develop energy selected pico-to nano-ampere beams of cluster ion with any size and chemical species by applying the observed phenomena.1) The ion yield of the group Vth element emitted from III-V semiconductive chemical compounds strongly depends on the electronic stopping power because multiplicity of holes produced in the valence band plays an important role in the surface ionization process of outgoing atoms.2) It has been found first that cluster ions are produced from the III-V semiconductive chemical compounds by swift heavy ion bombardment.3) Emission yields of cluster ions containing the group Vth elements show an incident energy dependence different from those composed of the group IIIth elements only. This is because the group Vth atoms have high ionization potentials and the ionization efficiency depends so much on the multiplicity of holes which increases with increasing electronic stopping power, as shown in the group Vth ions.4) Yields of cluster ions emitted from the semiconductive chemical compounds show a power law dependence on size whose exponent is independent of incident energy.5) Beam of cluster ions can be produced by using insulating and semiconductive materials.

我们以前发现，大的集群离子发射的电子碰撞占主导地位的速度范围内具有非常高的溅射产率。这些团簇离子的能量分布是非常狭窄的相比，通过线性碰撞级联过程中的核碰撞占主导地位的速度范围内发射的。本研究的目的是应用所观察到的现象，发展能量选择的皮安到纳安的具有任何尺寸和化学种类的团簇离子束。1）从III-由于价带中产生的空穴的多重性在出射电子的表面电离过程中起着重要的作用，因此，化合物的电子阻止本领强烈地依赖于化合物的电子阻止本领2）首次发现III-V族化合物在快速重离子轰击下产生团簇离子; 3）含V族元素的团簇离子发射产额与只含III族元素的团簇离子发射产额具有不同的入射能量依赖关系。这是因为Vth族原子具有高电离势，并且电离效率在很大程度上取决于空穴的多重性，空穴的多重性随着电子阻止本领的增加而增加，（4）从这些化合物中发射出的团簇离子产额与尺寸呈幂律关系，其指数与入射能量无关。用绝缘材料和屏蔽材料可以产生团簇离子束。