Interface properties study on SiC MOS with high-κ Al2O3 gate dielectric
In order to mitigate the electric field crowdingingate dielectrics and solve the reliability issue, high dielectric constant (κ) materials such as Al2O3 was applied in SiC metal-oxide-semiconductor (MOS) capacitors. High quality thin film Al2O3 was deposited on 4H-SiC by thermal atomic layer deposition (ALD), followed by post deposition annealing (PDA). The PDA was conducted in oxygen atmosphere at various temperatures from 900 °C to 1100°C. Apart from furnace annealing in oxygen, we also conducted rapid thermal annealing (RTA) in N2 atmosphere at 1000 °C by contrast. Based on the multi-frequency C-V method, an optimized annealing temperature of 1000 °C in oxygen atmosphere shows the best results, i.e., the low density of interface traps, leakage current, frequency dispersion and reasonably high κ value.