Temporal and Spatial Correlations in Electron-Induced Arcs of Adjacent Dielectric Islands

This paper investigates very short duration (<;1 ms) flashes caused by rapid discharge arcs from isolated, charged, insulating epoxy “glue dots” to an underlying grounded substrate while under electron bombardment. The possibility that a given arc might stimulate arcs in adjacent “glue dots” was investigated through coincidence correlation analysis, as was the dependence of such correlations with “glue dot” separation. Most arcs were found to be random localized events, which occurred only when accumulated charge produced an electric field large enough for electrostatic breakdown to occur. However, for 40-keV incident beams, significant temporal and spatial correlation were observed. It is hypothesised that at higher energies more samples are charged close to the breakdown field at any given time and that a discharge in one “glue dot” might cause a sudden electric field spike in neighboring “glue dots,” which could trigger premature arcing. Such stimulated arc rates might reasonably be expected to scale with electric field intensity. A power law fit to the arc data found a power of -1.06 ± 0.09, consistent with a field falling off inversely with separation distance for charges spreading out across a 2-D conducting surface.