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. [ABSTRACT FROM AUTHOR]