Hall Effect and Admittance Measurements of n-Channel 6H-SiC MOSFETs

In this paper we give a comparative study of two types of gate oxidation of n-channel 6HSiC MOSFETs. One set of transistors was fabricated using pyrogenic oxidation with no postoxidation annealing, and for the second set the oxide was grown in dry O2 with post-oxidation annealing. The lateral MOSFETs show a Hall mobility of ~ 75 cm2/Vs which is essentially same for both types of oxide. From the IV characteristics curves, the latter devices exhibit an average effective channel mobility of 72 (± 5) cm2/Vs, whereas the former has a value of 30 (± 3) cm2/Vs. From the capacitance and conductance measurements, the interface trap density for pyrogenicgrown oxide using is roughly a factor of 2 greater than those grown by dry oxidation. We found that the pyrogenic post-oxidation anneal at 1073K helps to reduce the interface states density and improves the effective channel mobility of 6H-SiC MOSFETs.