氧环境扫描电子显微分析:消除绝缘材料荷电效应的新方法  

Oxygen Environmental Scanning Electron Microscopy:A New Method for Elimination of Charging Effects on Insulating Materials

作　　者：张虹[1] 吉元[1] 权雪玲[1] 徐学东[1] 张隐奇[1] 郭汉生[1] 

机构地区：[1]北京工业大学固体微结构与性能研究所,北京100022

出　　处：《真空科学与技术学报》2005年第5期344-349,共6页Chinese Journal of Vacuum Science and Technology

基　　金：国家自然科学基金项目(No.60171024)

摘　　要：在环境扫描电镜(ESEM)中注入氧气,减少和消除绝缘样品表面在电子束辐照下产生的荷电效应。二次电子像的观察显示,在压力为130Pa^600Pa的ESEM中,氧气对Al2O3、Al(OH)3等氧化物、氢氧化物及生物样品的荷电补偿效果,优于常用的水蒸汽环境。通过吸收电流Ia的实时测试,评价了氧环境的荷电补偿效果。采用氧气减少表面荷电基于一个新的概念:在电子束的辐照下,电子受激解吸可造成表面氧亏损,使能带产生畸变,形成捕获电子的势阱。氧环境提供的氧离子可实现对氧空位的修复,从而消除了荷电效应。Oxygen injection into environmental scanning electron microscopy （ESEM） effectively reduces or eliminates charging effect on insulating sample surfaces under dectron irradiation. Secondary electron images clearly indicate that oxygen works much better than water vapor in charge compensation on many insulating surfaces, including metal oxides, Al2O3, metal hydroxides, Al（OH）, and biological samples in a pressure ranging from 130 to 600 Pa in ESEM. Current absorption Ia was measured in-situ to understand the mechanism of charge compensation in O2 environment. Under electron beam irradiation, high density of surface electron traps form because electron stimulated desorption results in oxygen depletion and energy band distortion on the surface. However, in oxygen environment, these oxygen vacancies can be easily filled by O ions. As a result, the charging effect cam be effectively eliminated.

关 键 词：荷电效应 氧环境 环境扫描电镜 AL2O3 AL(OH)3 

分 类 号：TB303[一般工业技术—材料科学与工程]