Weibull Statistics in Dielectric Breakdown; Theoretical Basis, Applications and Implications

A physical justification for the use of Weibull statistics in the assessment of dieelctric breakdown is presented in terms of a theoretical model of structural fluctuations in non-crystalline materials which has previously been applied to relaxation dynamics in such materials. A number of breakdown mechanisms have been considered and the relationship of the Weibull parameter to experimentally measurable relaxation data is outlined. The equivalence between the statistics of dynamic and static tests is explored and the implications of the Weibull statistics in extrapolating to working conditions noted. It is stressed that an important application of Weibull statistics is that the ability to construct a viable proof test is determined by the value of the time parameter.