27.12 MHz基片偏压在调控磁控溅射离子能量中的作用研究  

Influence of 27.12 MHz Bias on Properties of Magnetron Sputtering Ion Beam:A Methodological Study

作　　者：吴茂成[1] 叶超[1] 刘溪悦 Wu Maocheng;Ye Chao;Liu Xiyue(School of Physics Science and Technology,Soochow University,Suzhou 215006,China)

机构地区：[1]苏州大学物理科学与技术学院,苏州215006

出　　处：《真空科学与技术学报》2020年第4期373-380,共8页Chinese Journal of Vacuum Science and Technology

基　　金：国家自然科学基金项目(Grant No 11675118)。

摘　　要：在基片上施加射频偏压,调控入射离子能量特性,可以有效地控制薄膜生长与性能。常用的13.56 MHz射频基片偏压具有入射离子能量呈展宽发散分布、较强的高能离子轰击作用问题。为解决这些问题,本文通过提高射频偏压频率的方法,采用拒斥场能量分析技术,研究了27.12 MHz射频基片偏压对磁控溅射基片表面离子能量分布特性和离子通量密度性能的影响。结果表明,27.12 MHz射频基片偏压可以有效降低高能离子密度,提高低能离子密度,使离子能量更集中分布,从而降低高能离子对基片的轰击作用。离子能量分布特性的变化与基片偏压频率提高导致的离子渡越鞘层时间τi延长、离子与中性基团碰撞几率增大有关。碰撞几率增大使高能离子比例降低、低能离子比例增大,离子能量分布变窄,离子能量的发散降低。因此,提高基片射频偏压频率,可以降低离子能量的发散和高能离子对基片产生的不利作用。Herein,we addressed the problem of bombardment damage and over-sputtering etching,originated from wide energy spreading of ion beam,especially those high energy ions,in film growth by RF magnetron sputtering.The solution was a 27.12 MHz substrate bias.The influence of 27.12 MHz bias on the energy distribution of ion-beam was investigated with retarding field energy analyzer.The results show that a 27.12 MHz substrate bias made the difference.To be specific,the bias significantly decreased the density of high-energy ion and simultaneously increased the density of low-energy ion,markedly narrowing the energy spreading,obviously shifting the energy distribution of ion to low energy and greatly improving the film quality,possibly because the bias voltage greatly prolonged the transit time of ions(τi) across the sheath,resulting in significantly-increased collision cross-section between sputtering ion and neutrals,and a narrower energy distribution of the ion beam.

关 键 词：磁控溅射 基片偏压 离子能量分布 射频放电 

分 类 号：O539[理学—等离子体物理]