三维规则形貌影响下的二次电子发射特性研究

通过人工加工出特定的表面形貌来调控材料的二次电子发射特性已在诸多领域得到应用。规则表面形貌易于揭示抑制规律和影响机制对二次电子发射特性的影响，同时采用光刻、等离子刻蚀等工艺可以较好地实现特定设计的规则形貌，因此，在抑制微放电的研究初期或原理性试验验证过程中多采用定制的规则表面形貌。基于提出的电子与表面形貌相互作用的多代模型，以三维圆柱孔为例，采用蒙特卡罗方法系统研究了三维规则表面形貌的深宽比、占空比等参量影响二次电子产额、二次电子能谱以及出射角分布的规律。研究发现：规则形貌的深宽比越大，能谱展宽越强烈，形貌对出射角的选择性越强，二次电子产额的抑制效果越好，但该抑制效果存在饱和效应。在形貌不发生交叠时，增加占空比，可有效降低二次电子产额，由于圆柱孔出射电子占比较少，二次电子能谱与出射角分布接近于平面。所获得的三维规则表面形貌的二次电子发射特性对于全面评估其对微放电效应的影响提供了参考。

Influence of 3D regular surface morphology on secondaryelectron emission

It has been applied in many fields to customize specific surface morphology to control secondary electron emission of materials.The regular surface morphology can easily reveal the influence of the suppression and the influence mechanism on the secondary electron emission. Meanwhile, photolithography, plasma etching and other processes can better achieve the specific design of regular morphology. Therefore, custom regular morphology is often used in the initial research stage of multipactor or in the process of principle experimental verification. Taking the three dimensional cylindrical hole as an example, multi-generation Monte Carlo method which considers multiple interactions between electrons and complex surface morphology was used to systematically study the influence of regular morphology parameters such as depth width ratio and duty cycle ratio on secondary electron yield (SEY), secondary electron spectrum (SES) and emission angle distribution. It was found that the larger the depth width ratio of regular morphology is, the wider the SES broadening, the stronger the selectivity of the morphology to emission angle, and the better restraint effect of SEY, but the restraint effect is not indefinite. When the morphology does not overlap, SEY can also be effectively reduced by increasing the duty cycle ratio. However, due to the relatively small proportion of emitted electrons of the cylindrical hole compared with flat surface, the SES and the emission angle distribution is close to flat surface. The secondary electron emission properties of regular morphology obtained in the paper provide a reference for the comprehensive evaluation of its influence on multipactor effect.