SiO2/4H-SiC interface states reduction by POCl3 post-oxidation annealing

Interface state density (D_it) at SiO₂/4H-SiC interfaces is investigated using capacitance-voltage (C-V) characterization. Two different measurement methods for D_it determination (both C-V at different temperatures in the range of 80-300K and high frequency (HF) vs quasi static (QS) characteristics) have been used. A significant reduction of D_it is observed, almost one order of magnitude, after a post oxidation annealing (POA) in POCl₃ ambient, compared to as-grown dry oxidized sample.