AlGaN/AlN/GaN Metal-Oxide-Semiconductor High-Electron Mobility Transistor with Annealed Al2O3 Gate Dielectric

An AlGaN/AlN/GaN metal-oxide-semiconductor high-electron mobility transistors (MOS-HEMT) with an Al 2 O 3 insulator is studied. The post-deposition annealing (PDA) of Al 2 O 3 is conducted. The effects of PDA in an N 2 atmosphere on the performance of the MOS-HEMTs are studied. Experimental results demonstrate that the trap density in the Al 2 O 3 MOS diode is significantly decreased by annealing. Adding annealed Al 2 O 3 as a surface passivation and a gate oxide layer on HEMTs reduces gate leakage currents, increases the two-terminal reverse breakdown voltage, and improves the high-frequency performance of the HEMTs.