Atomic layer deposition of ZrO2 as gate dielectrics for AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors on silicon

In this Letter, the device performance of AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors (MISHEMTs) on silicon substrate using 10-nm-thick atomic-layer-deposited ZrO2 as gate dielectrics is reported. The ZrO2 AlGaN/GaN MISHEMTs showed improved maximum drain current density (Idmax) with high peak transconductance (gmmax) as comparison to Schottky-barrier-gate HEMTs (SB-HEMTs). Also compared to SB-HEMTs, reverse gate leakage current was four orders of magnitude lower and forward gate bias extended to +7.4 V. At energy from −0.29 eV to −0.36 eV, low interface trap state density evaluated by AC conductance and “Hi-Lo frequency” methods indicates good quality of atomic-layer-deposited ZrO2 dielectric layer.