Fabrication and characterization of the normally,off N-channel lateral 4H-SiC metal-oxide-semiconductor field-effect transistors

In this paper, the normally-off N-channel lateral 4H–Si C metal–oxide–semiconductor field-effect transistors（MOSFFETs） have been fabricated and characterized. A sandwich-（nitridation–oxidation–nitridation） type process was used to grow the gate dielectric film to obtain high channel mobility. The interface properties of 4H–Si C/SiO2 were examined by the measurement of HF I–V, G–V, and C–V over a range of frequencies. The ideal C–V curve with little hysteresis and the frequency dispersion were observed. As a result, the interface state density near the conduction band edge of 4H–Si C was reduced to 2 × 1011 e V-1·cm-2, the breakdown field of the grown oxides was about 9.8 MV/cm, the median peak fieldeffect mobility is about 32.5 cm2·V-1·s-1, and the maximum peak field-effect mobility of 38 cm2·V-1·s-1 was achieved in fabricated lateral 4H–Si C MOSFFETs.