Reduction of off-state drain current in AlN/[formula omitted] HEMT by trap state engineering

Abstract

In this work, we report various strategies to reduce the off-state drain leakage current (IOFF) in AlN/β−Ga2O3 high electron mobility transistor (HEMT) by 2D device simulation. We have investigated the effect of access region, channel doping concentration, barrier layer thickness, and trap state engineering on IOFF. The formation of a parallel channel deep into the substrate has been found to be responsible for large IOFF. All other strategies except trap state engineering have an incremental effect on IOFF. However, the device’s IOFF was reduced by around 12 orders of magnitude by trap-state engineering. Simultaneously, the on-state performance was unaffected, resulting in an elevated ION/IOFF current ratio of (1013). A steep subthreshold slope of 0.267 (V/dec) was also obtained. Further, we have investigated the impact of both donor- and acceptor-type traps on subthreshold characteristics. These promising results highlight the potential of AlN/β−Ga2O3 HEMT as a switch and for future high-power nanoelectronics applications.