Interface properties study on SiC MOS with high-κ Al2O3 gate dielectric

Abstract

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.