Dielectric breakdown from the nano- to millimeter scale:long known but still not well understood

摘要

Although the dielectric breakdown is a long known failure phenomenon of bulk and thinfilm insulation materials surprisingly there is no comprehensive study available which combinesbreakdown measurements of bulk and thin film insulators.We investigate the size and permittivitydependence of the breakdown strength from the millimeter down to the nanometer range.Forthin films the intrinsic breakdown strength is determined,and a dielectric expression based onthe mechanical analogue of the theoretical mechanical strength is presented.For the breakdownstrength of bulk materials,we developed an energy release rate based "fracture" model,which isable to describe unstable dielectric breakdown of ceramic and polymer insulators.The predictionsof the two models are discussed in the context of the experimental results.