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

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 (t _bb ~100 nm) is beneficial for obtaining low leakage current and high I _on /I _off ratio of approximately 10 ⁸ . While further increasing the AlGaN thickness can deteriorate the device performances because of the generation of more surface defects. The dynamic on-resistance (R _ON ) degradation measurements demonstrate that the proper AlGaN back barrier thickness (t _bb ) 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 R _ON .