Characterization of Sc2O3/SiO2/SiC MOS capacitors: role of annealing temperature on microstructural and electrical properties

Abstract

This study investigates the structural and electrical properties of Al/(Sc₂O₃/SiO₂/4H-SiC)/Ag MOS capacitors, focusing on the effects of the annealing temperature on the performance metrics. Sc₂O₃ films were deposited via electron beam deposition, while SiO₂ was grown through dry oxidation. The optimal annealing temperature was determined, alongside an analysis of the SiO₂ interfacial layer’s effect on the capacitors’ characteristics. Key findings reveal that increased annealing temperatures enhance the capacitance–voltage (C-V) and conductance-voltage (G-V) measurements. Specifically, capacitance (C_c) and conductance (G_c) significantly improved for the S-800 sample, reflecting enhanced interface quality and effective oxide state density (N_eff), which increased with temperature, peaking at 800 °C. Crystallite sizes varied from 249 Å to 309 Å, with lattice parameters and dislocation density exhibiting trends reflective of temperature increases, although anomalies were observed at 1000 °C. While series resistance (R_s) displayed no clear trend, the interface density of states (D_it) decreased, and parameters such as donor concentration (N_D), breakdown electric field maximum (E_m), and barrier height (φᵦ) diminished with higher annealing temperatures. Overall, the findings underscore annealing as a critical factor for optimizing MOS capacitor functionality, highlighting a balance between structural improvements and electrical performance metrics.