High On/Off Current Ratio and High V th/R on Stability GaN MIS-HEMTs With GaN/AlN Superlattices Barrier

In this work, the electrical characteristics and bias stress reliability of GaN/AlN superlattices (SLs) metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) with Al2O3 dielectric are experimentally investigated. In comparison to the conventional AlGaN barrier MIS-HEMTs, the GaN/AlN SLs MIS-HEMTs exhibit a higher ON/OFF current ratio ( <tex-math notation="LaTeX">10^10 </tex-math> ), higher gate forward breakdown voltage (BV) (15.2 V) and OFF -state BV (495 V), lower ON-resistance ( <tex-math notation="LaTeX">9.5~Ω </tex-math> /mm <tex-math notation="LaTeX">^-1 </tex-math> ). Moreover, the threshold voltage ( <tex-math notation="LaTeX">V_th </tex-math> ) shift and ON-resistance (R on) degradation under bias stress are further monitored. The GaN/AlN SLs MIS-HEMTs demonstrate excellent <tex-math notation="LaTeX">V_th </tex-math> and <tex-math notation="LaTeX">R_on </tex-math> stability, attributed to the superior dielectric/barrier interface quality and effective 2-D electron gas confinement provided by the GaN/AlN superlattice structure. These results ensure the superior performance and stability of GaN/AlN SLs MIS-HEMTs for power/RF applications.