AlGaN/GaN E-mode MOS-HEMT Using Atomic-Layer-Deposited HfLaOx as Gate Dielectric

In this paper, we report GaN MOS-HEMTs with high quality atomic-layer-deposited HfLaO _x as gate dielectric. The threshold voltage of the recessed gate MOS-HEMT can be enhanced from -6.2 V to 0.8 V. The E-mode GaN MOS-HEMT exhibits ideal subthreshold swing ~ 66 mV/dec and high on-off ratio of 1.2×10 ¹⁰ . Conductance method has been applied to reveal interface trap density Dit distribution between high-κ/III-N interface. Effective mobility of D-mode and E-mode MOSHEMTs are 1958 cm ² /V·s and 1483 cm ² /V·s, respectively. A high breakdown voltage of 840 V was achieved, thanks to suppressed gate leakage. The specific on-resistance of E-mode device is 1.86 mΩ·cm ² , which results in high power figure of merit (BV ² /R _on,sp ) of 380 MW/cm ² .