低能电子束照射电介质样品的二次电子特性简

 为阐明低能电子束照射下电介质样品的二次电子电流及产额的动态特性，将蒙特卡洛法和有限差分法相结合，建立了较为准确的电子散射、俘获、输运和自洽场等过程的数值计算模型；采用一个改进二次电子检测实验平台，准确测量了二次电子电流.模拟和实验结果表明，相对于电子束脉冲照射模式，电子束连续照射会导致二次电子产额明显降低.在连续照射模式下，随着电子束照射，二次电子电流和产额逐渐减小至一个稳定值.二次电子产额受入射电子束电流的影响较小，但随样品厚度的增大而增大.本文结果为提高扫描电镜成像质量、降低带电效应提供了理论指导，而且提供了依据二次电子特性研究样品参数的新思路.

SE Characteristics of Dielectrics Under Low-Energy Electron Beam Irradiation

To clarify secondary electron (SE) yield and current characteristics of dielectrics due to low-energy electron beam irradiation,we propose an electron scattering,trapping,transport and self-consistent numerical model by combining the Monte Carlo method and the finite difference method.By establishing an improved SE detection platform,we measure the emission SE current of dielectric samples.Results show that,comparing with the impulse electron beam irradiation,the SE yield will decrease evidently under the continuous electron beam irradiation.With irradiation,the SE current and yield reduce to a stable value gradually.Moreover,the SE yield varies slightly with electron beam current,but increases with the increase in the sample thickness.The results provide the theoretical guidance to improve the imaging quality and suppress the charging effect in modern scanning electron microscopy and a new thought for the parameter measurement of dielectrics according to SE characteristics.