Passivation of SiO2/4H-SiC interface defects via electron cyclotron resonance hydrogen-nitrogen mixed plasma pretreatment for SiC surface combined with post-oxidation annealing

We proposed an electron cyclotron resonance microwave hydrogen-nitrogen mixed plasma (HNP) pretreatment for 4H-SiC surface combined with post-oxidation annealing (POA) to improve the SiO2/SiC interface properties. Results revealed that HNP surface pretreatment effectively reduced the density of interface traps (Dit), which was closely correlated with interface flattening because of surface flattening, surface state (contaminants, adsorbates, and dangling bonds) reduction, and suppressed generation of interface defects during oxidation. Combined with POA, Dit was further decreased because of passivation of the formed defects after oxidation. The correlation among passivation, SiC surface properties, SiO2/SiC interface properties, and defect levels was established.