In-vacuum surface flashover of SiN, AlN, and etched SiO2 thin films at micrometre scales

We investigate the surface flashover voltage threshold for SiO${}_2$, SiN, and AlN thin films over micrometre scale lengths. Furthermore, we test the effects of different etching chemistries on SiO${}_2$ layers. We find that there is little significant difference between untreated SiO${}_2$ samples and those that have been etched with hydrogen fluoride or Transene AlPad Etch 639. SiN and AlN samples performed significantly better than all SiO${}_2$ samples giving a 45% increase in surface flashover voltage at a distance of 5 $\mu$m with the difference increasing with electrode spacing.