Investigation of the reliability of 4H-SiC MOS devices for high temperature applications

In this paper, the excellent reliability of 4H-SiC MOS devices during high temperature operation is demonstrated for a gate oxide processed in N 2O. A temperature dependent Fowler-Nordheim analysis is used to show that statistical energy spreading accounts for only part of the reported temperature induced barrier height degradation. Poole-Frenkel current caused by acceptor like traps in the oxide due to carbon interstitials is proposed to be responsible for the additional current observed. Temperature and electric field acceleration of the time to dielectric breakdown is investigated at elevated temperatures in order to predict the expected MOS lifetime during high temperature operation.