Recessed-Gate GaN Metal-Insulator-Semiconductor High-Electron-Mobility Transistor Using a Dual Gate-Insulator Employing TiO₂/SiN

Abstract

In this work, we present a normally-off recessed-gate AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistor (MIS-HEMT) using a TiO₂/SiN dual gate-insulator. We analyzed the electrical characteristics of the proposed device and found that the dual gate-insulator device achieves higher on-state currents than the device using a SiN gate-insulator because the high-k insulator layer of the dual gate-insulator improves the gate-controllability. The device using a TiO₂/SiN gate-insulator shows better gate leakage current characteristics than the device with only TiO₂ gate-insulator because of the high quality SiN gate-insulator. Therefore, the device using a dual gate-insulator can overcome disadvantages of a device using only TiO₂ gate-insulator. To better predict the power consumption and the switching speed, we simulated the specific on-resistance (R_{on, sp}) according to the gate-to-drain distance (L_GD) using the two-dimensional ATLAS simulator. The proposed device exhibits a threshold voltage of 2.3 V, a maximum drain current of 556 mA/mm, a low R_{on, sp} of 1.45 mΩ·cm², and a breakdown voltage of 631 V at an off-state current of 1 μA/mm with V_GS = 0 V. We have confirmed that a normally-off recessed-gate AlGaN/GaN MIS-HEMT using a TiO₂/SiN dual gate-insulator is a promising candidate for power electronic applications.