金属规则表面形貌影响二次电子产额的解析模型

表面形貌是影响二次电子发射特性的重要因素, 但目前仍缺乏刻画这一影响规律的解析模型. 本文通过分析发现表面结构的遮挡作用是影响二次电子发射特性的主要因素. 基于二次电子以余弦角分布出射的规律, 提出了建立表面形貌参数与二次电子产额之间定量关系的方法, 并以矩形槽和三角槽为例, 建立了电子正入射和斜入射时的一代二次电子产额的解析模型. 将推导的解析模型与Monte Carlo模拟结果和实验结果进行了比较, 结果表明本文建立的模型能够正确反映规则表面形貌的二次电子产额. 本文的模型对于反映常用规则结构影响二次电子出射的规律以及指导通过表面结构调控二次电子发射特性都具有参考价值.

Analytical model of secondary electron yield from metal surface with regular structures

An analytical model of secondary electron (SE) emission (SEE) from metal surface with regular structure is presented. In this model, the quantitative relationship between the SE emission yield (SEY) and surface topography is examined. Using the idea of multi-generation for SE emission, the first-generation of SEs is considered as being dominant in total SEs. The shielding effect of the surface structures on the SE is found to be the main factor influencing final SEY. On the basis of the cosine distribution of secondary electrons emission direction, the quantitative relationship between the SEY and surface topography parameters is revealed. Then taking the rectangular and triangular grooves for example, the analytical formulas of first-generation SEY are derived for both normal and oblique incidence. The analytical results are then verified with the Monte Carlo simulation results and experimental data. The results show that a rectangular groove with a bigger depth-to-width ratio can suppress the SEE more efficiently. For a triangular groove, owing to having both enhancing and suppressing effects on SEE, a small groove angle is required for effective SEE suppression. The present analytical model gives an insight into the relationship between the SEY and the surface topography parameters and is helpful for the structure design to modify SEY.