AlGaN/GaN Metal–Oxide–Semiconductor High-Electron Mobility Transistor With Liquid-Phase-Deposited Barium-Doped $\hbox {TiO}_{2}$ as a Gate Dielectric

Barium-doped TiO₂ films deposited on GaN layers at low temperature through a simple liquid phase deposition method is investigated. The use as a gate dielectric in AlGaN/GaN metal-oxide-semiconductor high-electron mobility transistors (MOSHEMTs) is also demonstrated. The electrical characteristics of the MOS structure on n-doped GaN show that the leakage current density is about 5.09 × 10^-9 A/cm² at 1 MV/cm, and the breakdown field is more than 13 MV/cm. The maximum drain current density of the AlGaN/GaN MOSHEMTs is higher than that of HEMTs, in which a wider gate voltage swing and a lower subthreshold swing (110 mV/decade) are obtained. The gate leakage current density is significantly improved, and the gate pulse measurement shows that the current collapse is more suppressed for MOSHEMTs.