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

Interface state density (Dit) at SiO2/4H-SiC interfaces is investigated using capacitance-voltage (C-V) characterization. Two different measurement methods for Dit 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 Dit is observed, almost one order of magnitude, after a post oxidation annealing (POA) in POCl3 ambient, compared to as-grown dry oxidized sample.