SiC Nitridation by NH3 Annealing and Its Effects in MOS Capacitors with Deposited SiO2 Films

Silicon carbide (SiC) thermal nitridation followed by oxide deposition is a route to confine nitrogen at the SiO 2 /SiC interfacial region. To investigate its effects, incorporation of nitrogen into SiC by annealing in isotopically enriched ammonia was performed. This incorporation led mainly to silicon nitride-like formation. The observed silicon oxynitrides originated mainly from oxygen incorporation due to air exposure of samples. Metal–oxide–semiconductor structures formed by SiO 2 deposition on nitrided SiC samples presented poor electrical quality, even when different postdeposition annealing conditions in argon were applied. Such results suggest that this route must be modified to allow nitrogen incorporation and avoid electrical degradation.