Reduction of interface and oxide traps in SiO2/GaN MOS structures by oxygen and forming gas annealing

The effect of post-deposition annealing on the electrical characteristics of SiO2/GaN MOS devices was investigated. While the key to the improvement was using oxygen annealing to form an interfacial GaO x layer and forming gas annealing to passivate the remaining defects, caution must be taken not to produce a fixed charge through reduction of the GaO x layer. By growing the GaO x layer with oxygen annealing at 800 °C and performing forming gas annealing at a low temperature of 200 °C, it became possible to suppress the reduction of GaO x and to reduce the interface traps, oxide traps, and fixed charge simultaneously.