Improving the Barrier Height Uniformity of 4H—SiC Schottky Barrier Diodes by Nitric Oxide Post-Oxidation Annealing

We improved the characteristics of 4H-SiC Schottky barrier diodes (SBDs) by post-oxidation annealing in nitric oxide ambient (NO POA). Unlike the sacrificial oxidized SBDs, the SBDs with added NO POA exhibited highly uniform Schottky barrier height and nearly ideal breakdown voltage of 1990 V. Time-of-flight secondary ion mass spectroscopy revealed nitrogen pileup at the sacrificially oxidized SiC surface after NO POA. We believe that NO POA electrically passivated the detrimental residual carbon at the SiC surface by forming C-N bonds, improving the performance of the SBDs.