Influence of Deep-Level Traps on the Breakdown Characteristics of AlGaN/GaN High Electron Mobility Transistors

In this paper, we investigate the influence of the deep-level traps in the GaN buffer layer on the breakdown characteristics of AlGaN/GaN high electron mobility transistors. The deep-level traps are assumed to be acceptor type with single peak distribution in energy. The leakage current through the GaN buffer layer is effectively suppressed with the presence of deep-level traps in the buffer region. Moreover, the traps charged with electrons further improve the uniformity of the electric field along the channel. The breakdown strength of the devices is dramatically enhanced by the above two factors. With trap density increasing from 1 x 10(15) cm(-3) to 5 x 10(16) cm(-3), the breakdown voltage of AlGaN/GaN HEMTs is significantly improved from 10 V to 1351 V with 5 mu m gate-drain spacing, while negligible negative impact on ON-state resistance is observed.