Influence of AlGaN back barrier layer thickness on the dynamic ron characteristics of AlGaN/GaN HEMTs

Abstract

AlGaN back barrier with different thickness is used in AlGaN/GaN high electron mobility transistors (HEMTs) to evaluate the device performances. It shows that a proper AlGaN back barrier thickness (tbb ∼100 nm) is beneficial for obtaining low leakage current and high Ion/Ioff ratio of approximately 108. While further increasing the AlGaN thickness can deteriorate the device performances because of the generation of more surface defects. The dynamic on-resistance (RON) degradation measurements demonstrate that the proper AlGaN back barrier thickness (tbb) can not only improve the 2DEG confinement, but also prevent electrons penetrating into buffer layer. Thus, it results in the reduction of trapping effect and then the improvement of dynamic RON.