Influence of post-deposition annealing on interface characteristics at Al2O3/n-GaN

We investigated the influence of post-deposition annealing (PDA) on interface characteristics of Al₂O₃/n-GaN capacitors in shallow (around E_c) and deep (around E_v) band regions. Interface state density (D_it) estimated by conductance method increased in shallow band region at Al₂O₃/n-GaN interface after PDA at 900°C. In contrast, another D_it estimated by photo-assisted C-V measurement was improved in deep band region and the interface fixed charge estimated from Vfb shift also decreased after PDA at 900°C.