扫描电子显微学中二次电子发射过程的蒙特卡洛模拟(英文)

Monte Carlo simulation of secondary electron emission in SEM

利用蒙特卡洛模拟固体中电子散射轨迹的计算方法 ,系统地研究了扫描电镜中二次电子信号的发射过程。该模拟电子与固体相互作用的蒙特卡洛模型包含了级联二次电子产生的过程 ,并且采用光学介电函数方法描述电子的能量损失和相伴随的二次电子激发。由于模拟计算可以给出背散射电子和二次电子的绝对产额 ,以及它们随加速电压和样品的原子序数的变化关系 ,因此可以用于模拟元素衬度和形貌衬度像。还计算得到了关于二次电子产生和发射的其它分布 。

The emission of secondary electron signals in SEM have been studied systematically by a Monte Carlo simulation of electron scattering trajectories in solids. The simulation is based on our previous Monte Carlo model of electron interaction with solids including cascade secondary electron production. An optical dielectric function approach has been used to describe electron energy loss and the associated secondary electron excitation process. The simulation enables the calculation of absolute yields of backscattering electrons and secondary electrons as a function of atomic number and primary beam energy and, hence, the elemental and topographical imaging contrast. Meanwhile, various distributions about secondary electron production and emission have been obtained and compared with experiments.