Structural, chemical, and metal-oxide-semiconductor characteristics of RF magnetron sputtered thulium oxide passivation layer on 4H-silicon carbide substrate

Abstract

Thulium oxide (Tm2O3) passivation layer (PL) deposited on 4H-silicon carbide (SiC) that was subjected to postdeposition annealing at 700 °C in forming gas-oxygen-forming gas ambient was reported for the first time in this work. X-ray photoelectron spectroscopy characterization revealed the success of annealing process in minimizing the concentration of oxygen vacancies and also curbed the presence of TmO suboxide bonding in the annealed Tm2O3 PL. In addition, XPS characterization has also disclosed the incorporation of nitrogen ions into the Tm2O3 lattice through the annealing process in which grazing incidence X-ray diffraction has also revealed the shift of detected peaks with regards to Tm2O3 phases to small diffraction angles. Although X-ray reflectivity measurements have disclosed the formation of thicker SiO2 interfacial layer (IL) for the annealed Tm2O3 PL, the acquisition of a higher dielectric constant (k) by the annealed PL when compared to as-deposited PL has suggested that the formation of SiO2 IL has minimal effect toward the k value of annealed PL. Metal-oxide-semiconductor characteristics of the annealed Tm2O3 PL on 4H-SiC was systematically reported in this letter.