Interfacial modification mechanism of ALD-SiO2/4H-SiC heterojunction by synergistic nitrogen–oxygen-atmosphere RTA

In this work, the interfacial modification of the ALD-SiO2/4H-SiC heterojunction with synergistic nitrogen–oxygen-atmosphere (N2/O2) rapid thermal annealing (RTA) and its physical mechanism have been systematically studied. Atomic layer deposition (ALD) can effectively suppress the carbon clusters generation at the SiO2/4H-SiC heterojunction interface and RTA in the synergistic N2/O2 can further reduce the interface states density, the near-interface-oxide-trap (NIOT) density and the leakage current. Oxygen can repair carbon-related defects, and nitrogen helps passivate carbon-related traps and dangling bonds. The synergistic N2/O2 RTA can enhance the interfacial passivation efficiency by converting sp3 carbon clusters into sp2 phases. These demonstrate that the proposed synergistic N2/O2 RTA associated with SiO2 deposition by ALD is a potential way to substitute the conventional toxic nitrous oxides annealing and high-budget thermal oxidation, which promotes the property and reliability of SiC devices.