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

TL;DR

This study measures the surface flashover voltage of SiO2, SiN, and AlN thin films at micrometre scales, revealing that SiN and AlN outperform SiO2, with etching chemistry having minimal impact on SiO2 performance.

Contribution

It provides new comparative data on flashover thresholds for different thin films and the effects of etching on SiO2 at micrometre scales.

Findings

SiN and AlN have 45% higher flashover voltage than SiO2 at 5 μm.

Etching chemistries do not significantly affect SiO2 flashover voltage.

Performance difference increases with electrode spacing.

Abstract

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.