Speaker: Prof. Anthony O’Neill, Newcaslte University, UK

Abstract— High performance 4H-SiC MOSFETs have been fabricated, having a peak effective mobility of 265 cm²/V.s, and a peak field effect mobility of 154 cm²/V.s, in 2 µm gate length MOSFETs.  The gate stack was designed to minimise interface states and comprised a 0.7 nm thermally grown SiO₂ on 4H-SiC, followed by Al₂O₃ and a metal gate contact. In this way carbon remaining following SiC oxidation is significantly reduced. A density of interface traps in the range 6×10¹¹ – 5×10¹⁰cm^-2eV^-1 is also obtained. Temperature dependent electrical data reveals that the high mobility results from conduction being phonon-limited rather than Coulomb-limited. Furthermore, universal mobility in these 4H-SiC MOSFETs is shown to be up to 50% of that observed in Si devices. Expressions for electric field dependent contributions to mobility are obtained.  A steep sub-threshold slope of 127 mV/dec indicates low electrical defect density. A temperature coefficient of -4.6 mV/K in threshold voltage is similar to that in Si MOSFETs.