(Invited) Progress in Buried Grid Technology for Improvements in on-Resistance of High Voltage SiC Devices

Abstract

Buried grid technology is suggested to protect field sensitive device areas from high electric field in order to improve the high temperature and high voltage performance of SiC devices. More than three orders of magnitude lower leakage currents have been demonstrated at high temperature operation. The drawback is that the total resistance increases due to the introduction of the buried grid leading to higher voltage drop at rated current and higher conduction losses. In this paper, we discuss doping and barrier engineering methods in order to take full advantage of the superior shielding effect of the buried grid technology and at the same time minimize the effect on the current conduction. As example, the design considerations for a 1200V SiC buried grid JBS diode in terms of epi structure doping as well as buried grid properties is comprehensively investigated to optimize the on-state condition.