Investigation of structural and electrical caracterisation of Sc2O3 dielectric layer in SiC base MOS technology

This thesis presents a detailed study of the annealing temperature-dependent structural and electrical properties of scandium oxide (Sc2O3) grown, using an electron beam evaporation system, on a 4H-SiC substrate, with XRD, C-V and G/ω-V measurements conducted to analyze its characteristics. In order to enhance capacitor performance, SiO₂ was coated between Sc₂O₃ and 4H-SiC substrate. From XRD measurements, although the lattice parameters, strain and density dislocation increased, crystallite size decreased with increasing annealing temperature was obtained. Moreover, it was also observed that the optimum annealing temperature was found to be 800 °C with optimal crystallization. From the electrical measurements, it was obtained that the higher annealing temperature enhances capacitance stability and lowers interface state density, resulting in flat band voltage adjustment. The measured capacitance and conductance's values due to the series resistance were corrected and it was obtained that the electrical properties was significantly affected by series resistance. The result indicated that both series resistance and interface states must be taken into account during the electrical characterization. Interface state density decreased while effective oxide state density increased with the increase in annealing temperature. The existing of thermally grown SiO₂ between the Sc2O3 thin film and SiC substrate enhanced the device of performance with rising annealing temperature.