Ozone oxidation of 4H-SiC and flat-band voltage stability of SiC MOS capacitors

Abstract

We investigate the effect of ozone (O3) oxidation of silicon carbide (SiC) on the flat-band voltage (V fb) stability of SiC metal–oxide–semiconductor (MOS) capacitors. The SiC MOS capacitors are produced by O3 oxidation, and their V fb stability under frequency variation, temperature variation, and bias temperature stress are evaluated. Secondary ion mass spectroscopy (SIMS), atomic force microscopy (AFM), and x-ray photoelectron spectroscopy (XPS) indicate that O3 oxidation can adjust the element distribution near SiC/SiO2 interface, improve SiC/SiO2 interface morphology, and inhibit the formation of near-interface defects, respectively. In addition, we elaborate the underlying mechanism through which O3 oxidation improves the V fb stability of SiC MOS capacitors by using the measurement results and O3 oxidation kinetics.