Power semiconductor devices are widely used as high voltage applications to inverters and motor drivers, etc. The blocking voltage is one of the most important parameters for power semiconductor devices. And cause of junction curvature effects, the breakdown voltage of the device edge and device unit cells was found to be lower than the ``ideal`` breakdown voltage limited by the semi-infinite junction profile. In this paper, Propose the methods for field ring design by DOE (Design of Experimentation). So The field ring can be improve for breakdown voltage and optimization.
