Influence of channel/back-barrier thickness on the breakdown of AlGaN/GaN MIS-HEMTs

The leakage current and breakdown voltage of Al Ga N/Ga N/Al Ga N high electron mobility transistors on silicon with different Ga N channel thicknesses were investigated.The results showed that a thin Ga N channel was beneficial for obtaining a high breakdown voltage,based on the leakage current path and the acceptor traps in the Al Ga N back-barrier.The breakdown voltage of the device with an 800 nm-thick Ga N channel was 926 V@1 m A/mm,and the leakage current increased slowly between 300 and 800 V.Besides,the raising conduction band edge of the Ga N channel by the Al Ga N back-barrier lead to little degradation for sheet 2-D electron gas density,especially,in the thin Ga N channel.The transfer and output characteristics were not obviously deteriorated for the samples with different Ga N channel thickness.Through optimizing the Ga N channel thickness and designing the Al GaN back-barrier,the lower leakage current and higher breakdown voltage would be possible.