非导电样品荷电效应的吸收电流评价方法  

Evaluation of charging effect on the non-conductive specimens by absorbe current measurement

作　　者：吉元[1] 张虹[1] 史佳新[1] 何焱[2] 吕长志[2] 徐学东[1] 张隐奇[1] 郭汉生[1] 

机构地区：[1]北京工业大学材料科学与工程学院,北京100022 [2]北京工业大学电子信息与控制工程学院,北京100022

出　　处：《电子显微学报》2004年第3期265-268,共4页Journal of Chinese Electron Microscopy Society

摘　　要：在扫描电镜(SEM)中,通过记录和实时处理电子束辐照样品过程中产生的吸收电流Ia,评价非导电样品的荷电效应。对于非导电样品,Ia的绝对值很小,且变化幅度很大,这是电荷在非导电样品表面被捕获、积累和释放过程的直接反映。此外,Ia还可用来评价荷电补偿(改变环境压力、改变成像参数及对样品表面进行导电处理)的效果。A measuring system of absorbe current I_a was established on a scanning electron microscope (SEM). The charge amount on non-conductive samples under electron beam irradiation in SEM could be estimated by recording and in-situ processing the absorbe current intensity I_a. Compared with the conductive samples, the Ia values of the insulate samples were small and unstable. It was the direct reflection of the process when electrons were trapped, accumulated and detrapped on the surface of an insulate samples. Furthermore, the value of Ia was used to evaluate the effect of charging compensation methods, such as change of environmental pressure, imaging parameters and specimen electrically coating. With increasing the pressure of 1.0×10^(-2) Pa to 2.0×10^(-2)Pa, the charging phenomenon on polycrystalline Al_2O_3 was reduced and the corresponding Ia values increased. The I_a fluctuation values indicated that the charging effects of Al_2O_3 haven't been eliminated at the pressure of 2.0×10^(-2) Pa. The Au-coated Al_2O_3-SiO_2 sample was charge-free, and its I_a value increased and became stable obviously.

关 键 词：扫描电镜 荷电效应 吸收电流 非导电材料 荷电补偿 

分 类 号：O441[理学—电磁学]