Weibull Statistical Dielectric Breakdown in Polyimide up to 400°C

In spite of the growing maturity of silicon carbide (SiC) technology, several difficulties still remain and limit its use for high temperature applications up to 200degC. Due to its excellent physical properties, SiC material offers the ability to design electronic devices working at junction (or ambient) temperature and at power level much higher than those of the present silicon based semiconductors. Thus, the environment of the SiC die will endure severe electrical and thermal stresses. Particularly, the passivation layer must present good thermal stability of its dielectric strength, which must remain high enough to ensure a proper electrical insulation on top of the SiC surface. In this study, polyimide material has been chosen as a candidate for SiC power device passivation. This paper presents the changes of the dielectric strength of a BPDA/PPD polyimide for temperatures ranging up to 400degC.