Enhanced channel mobility of 4H–SiC metal–oxide–semiconductor transistors fabricated with standard polycrystalline silicon technology and gate-oxide nitridation

Abstract

This work presents improved channel mobility of n-channel metal–oxide–semiconductor field-effect transistors (MOSFETs) on 4H–SiC, achieved by gate-oxide nitridation in nitric oxide. Lateral enhancement mode MOSFETs were fabricated using standard polycrystalline silicon gate process and 900 °C annealing for the source and drain contacts. The low field mobility of these MOSFETs was as high as 48 cm2/Vs together with a threshold voltage of 0.6 V, while the interface state density—determined from the subthreshold slope—was about 3×1011 eV−1 cm−2. The 43-nm-thick gate oxide of coprocessed metal–oxide–semiconductor structures exhibited a breakdown field strength of 9 MV/cm.