Influence of barrier design on current collapse in high voltage AlGaN/GaN HEMTs

Simultaneous measurements of surface potential and drain current detrapping transients in AlGaN/GaN HEMTs, performed on devices with two different epitaxial structures, show that the predominant location of charge trapping is affected more strongly by device design than by surface passivation or buffer defects. Experiments also show that AlGaN traps dominate current collapse in devices with thick AlGaN barrier layers.