Optimization of silver nanocolumnar coatings made by glancing angle deposition with magnetron sputtering to reduce the multipactor effect

Abstract

In this work, glancing angle deposition with magnetron sputtering has been used to fabricate nanocolumnar coatings made of silver. We have found that a highly collimated flux of atoms is important to achieve a well-defined columnar structure. Depending on the deposition parameters, several morphologies can be obtained, such as tilted or vertical nanopillars with different lengths. The secondary electron emission yield (SEY) from these nanostructured coatings has been measured, and it is lower than that obtained from flat silver, especially for those coatings with higher aspect ratio. The search of low-SEY coatings fabricated by simple techniques is of interest for high power RF devices in vacuum (for instance spacecraft equipment or particle accelerators apparatus), the main goal being the reduction of the resonant avalanche electron discharge that is known as the multipactor effect.