Excellent-Performance AlGaN/GaN Fin-MOSHEMTs with Self-Aligned Al_2O_3 Gate Dielectric

AlGaN/GaN fin-shaped metal-oxide-semiconductor high-electron-mobility transistors (fin-MOSHEMTs) with different fin widths (300 nm and 100 nm) on sapphire substrates are fabricated and characterized. High-quality self-aligned Al_2O_3 gate dielectric underneath an 80-nm T-shaped gate is employed by aluminum self-oxidation, which induces 4 orders of magnitude reduction in the gate leakage current. Compared with conventional planar MOSHEMTs, short channel effects of the fabricated fin-MOSHEMTs are significantly suppressed due to the tri-gate structure, and excellent dc characteristics are obtained, such as extremely flat output curves, smaller drain induced barrier lower, smaller subthreshold swing, more positive threshold voltage, higher transconductance and higher breakdown voltage.