High Temperature Nitridation of 4H-SiC MOSFETs

This paper presents and analyse the experimental results of 4H-SiC(0001) lateral MOSFETs and MOS capacitors with gate oxides grown directly in N2O environment or in O2 ambient followed by a N2O post oxidation annealing process. Different nitridation temperatures of 1200°C, 1300°C, 1400°C and 1500°C have been investigated. Results have demonstrated that at high temperature (>1200°C) there is a significant improvement in the interface trap density (~1.5×1011 cm-2eV-1 at 0.2 eV) and field effect channel mobility (19 cm2/V.s) of 4H-SiC MOSFET compare with those at lower temperature (1×1012 cm-2eV-1 at 0.2 eV and 4 cm2/V.s). Among those nitridation temperatures, 1300°C has found to be the most effective in increasing the field effect channel mobility and reducing threshold voltage.