Dielectric breakdown toughness from filament induced dielectric breakdown in borosilicate glass

The dielectric breakdown strength of borosilicate glass was measured as a function of the length of a conducting filament in order to determine the critical energy release for the growth of a breakdown channel. The concept is similar to the experimental determination of the toughness in fracture mechanics and based on a Griffith type model for the electrical energy release rate in dielectric materials with space charge limited conductivity. By Focused-Ion-Beam-milling and Pt-deposition, up to 100 μm long conductive channels were fabricated in 163 μm thick borosilicate glass substrates. The dielectric breakdown strength of substrates with filaments longer than 30 μm could be very well described by a 1filamentlength -dependence predicted by the model Schneider, 2013. With these results for the first time a critical energy release rate for dielectric breakdown was determined being 6.30 ± 0.95 mJ/m.