High On/Off Current Ratio and High Vth/Ron 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 (<inline-formula> <tex-math notation="LaTeX">$10^{{{10}}}$ </tex-math></inline-formula>), higher gate forward breakdown voltage (BV) (15.2 V) and OFF -state BV (495 V), lower ON-resistance (<inline-formula> <tex-math notation="LaTeX">$9.5~\Omega $ </tex-math></inline-formula>/mm<inline-formula> <tex-math notation="LaTeX">$^{{-{1}}}$ </tex-math></inline-formula>). Moreover, the threshold voltage (<inline-formula> <tex-math notation="LaTeX">$V_{{\text {th}}}$ </tex-math></inline-formula>) shift and ON-resistance (R on) degradation under bias stress are further monitored. The GaN/AlN SLs MIS-HEMTs demonstrate excellent <inline-formula> <tex-math notation="LaTeX">$V_{{\text {th}}}$ </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">$R_{{\text {on}}}$ </tex-math></inline-formula> 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.