二维混合结构网格电场数值模拟及其在低能电子枪设计中的应用

Design Optimization of Low Energy Electron Gun: A Simulation Study with Hybrid Mesh Model

在半导体行业中,低能电子枪是样品二次发射系数测量和样品表面电荷中和的关键部件。为了给低能电子枪提供设计参考,本文采用二维混合结构网格电场数值模拟计算方法构造了不同结构和栅极电位的电子枪模型,研究了不同模型结构对束斑和束流的影响。结果表明,随着栅极和阳极间距的增大,电子束的放大倍率和束流会降低;随着栅极孔径的增加,电子束的放大倍率会降低,束流会逐渐达到饱和点;随着栅极电位增大,栅极对电子束的会聚作用逐渐减弱,电子束的束流呈上升趋势并最终达到饱和点。

The electric field in a miniaturized low energy electron gun,used for IC chip fabrication and comprising the complicated cathode/grid/anode structures held at specific potentials,were mathematically formulated with 2 D hybrid mesh model,theoretically analyzed and numerically simulated in finite element method for the e-gun design optimization.The influence of the e-gun structures and models on the e-beam spot/current/trajectory was investigated.The simulated results show that the grid/anode distance,grid-aperture and grid potential all have a major impact.For example,as the grid/anode distance increases,the e-beam current/amplification decrease;as the grid-aperture increases,the e-beam magnification decreases and the e-beam current gradually increases to saturation.In addition,an increasing grid-potential slowly de-focuses the e-beam and steadily increases the e-beam current to saturation.