Improved Inversion Channel Mobility in Si-face 4H-SiC MOSFETs by Phosphorus Incorporation Technique

We propose a new technique to fabricate 4H-SiC metal-oxide-semiconductor field-effect transistors (MOSFETs) with high inversion channel mobility. P atoms were incorporated into the SiO2/4H-SiC(0001) interface by post-oxidation annealing using phosphoryl chloride (POCl3). The interface state density at 0.2 eV from the conduction band edge was reduced to less than 1 x 10(11) cm(-2)eV(-1) by the POCl3 annealing at 1000 degrees C. The peak field-effect mobility of 4H-SiC MOSFETs on (0001) Si-face processed with POCl3 annealing at 1000 degrees C was approximately 90 cm(2)/Vs. The high channel mobility is attributed to the reduced interface state density near the conduction band edge.