Improved fault localization method for power devices

Fault localization for power device is difficult due to their special structure with a thick metal layer on the surface as the testing terminal. This layer enhances the thermal diffusion and blocks the photon emission, which restricts the function of LC analysis, PEM or OBIRCH. The experiment shows that using the thinning layer like the barrier layer as the terminal after removing the most of the thick metal, the device remains the same status, while the PEM and OBIRCH work with high efficiency and defect could be located with much higher accuracy. The method is successfully applied for FA of conventional Power MOS, Super Junction, Diode and IGBT devices.