Demonstration of p-GaN/AlGaN/GaN High Electron Mobility Transistors With an Indium-Tin-Oxide Gate Electrode

In this study, p-GaN/AlGaN/GaN high electron mobility transistors (HEMTs) with indium-tin-oxide (ITO) gate electrodes are demonstrated. The DC measurements for the devices show a drain current ( \text{I}_{\mathrm{ D}} ) of 438 mA/mm at a \text{V}_{\mathrm{ D}} and a \text{V}_{\mathrm{ G}} of 10 and 8 V, respectively. A maximum {g} _{\mathrm{ m}} of 92.1 mS/mm and a specific ON-resistance ( \text{R}_{\mathrm{ on}}\cdot {\mathrm{ A}} ) of 1.86 \text{m}\Omega cm 2 are obtained. Furthermore, the robustness of the ITO gate electrode atop the p-GaN layer under the forward gate bias is studied, indicating stable \text{I}_{\mathrm{ G}}-{\mathrm{ V}}_{\mathrm{ G}} and \text{I}_{\mathrm{ D}}-{\mathrm{ V}}_{\mathrm{ G}} characteristics for a gate voltage of less than 11 V, which is higher than the compared device with Ni/Au Schottky gate contact. Therefore, ITO gate electrodes, which are compatible with the Light-emitting diode (LED) process, are a promising alternative for p-GaN HEMT technologies.