Dielectric Breakdown of Thinned BaO-Al2O3-B2O3-SiO2 Glass

The dielectric breakdown behavior of alkali-free glass was determined as a function of thickness and surface roughness. The thickness of commercially available glass (as-received thickness=50 mu m) was reduced to a range of thicknesses between 47 and 5 mu m by chemical etching. The RMS surface roughness of the as-received glass was in the range of 0.14-0.47 nm, and the surface roughness increased to up 10 nm after etching; it was also found that agitating the etching solution by ultrasound reduced the overall surface roughness. The evaluation of these samples revealed that the dielectric breakdown strength increased as the thickness decreased. However, the Weibull modulus representing the distribution of dielectric strengths showed a dependence on the surface roughness of the etched glass. A power law dependence, E-B proportional to d-n, where d is the glass thickness and n=0.14 and 0.86, has been found to fit the data in the respective thickness ranges of 5-20 and 25-50 mu m. Self-healing behavior, which allows the dielectric to continue to support a high electric field after breakdown, was found to be more likely as the dielectric layer thickness decreased. The susceptibility to self healing was correlated with the stored electrostatic energy and latent heat of vaporization for the gold electrode material.