蒙特卡罗法模拟薄样品中低失能近轴背散射电子

用蒙特卡罗方法模拟计算了薄样品中的高能同轴背散射电子的背散射率和厚度衬度.结果指出用较大的探测能量窗口和大的探测角可在确保厚度衬度的前提下增强信噪比.大的入射能量虽有利于厚度衬度,但不利于提高信噪比.薄膜沉积在异质衬底上的模拟结果显示,虽然背散射率中包含有衬底材料的信息,但还是膜层厚度的单调变化函数,有可能通过背散射率的测量来判定薄膜厚度.

Monte Carlo Simulation of Low Loss Energy and Coaxial Backscattered Electrons in a Thin Film Target

By using the Monte Carlo method, we simulate the backscattering coefficient and the thickness contrast of low loss energy and coaxial backscattered electrons in thin film targets. The results show that the use of greater values of energy loss window and detection angle can ameliorate the thickness contrast and the ratio signal to noise at the same time. Though a greater value of primary energy enhances the thickness contrast, however it is not favorable for ratio signal to noise. The simulation results of a thin film deposed on substrate show that the information of substrate is consisted in the total backscattering coefficient which is a linear function of film thickness, so it is possible to determinate the film thickness by measuring the backscattering coefficient.