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 (Ron, sp) according to the gate-to-drain distance (LGD) 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 Ron, sp of 1.45 mΩ·cm2, and a breakdown voltage of 631 V at an off-state current of 1 μA/mm with VGS = 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.

A Review on the Progress of Optoelectronic Devices Based on TiO2 Thin Films and Nanomaterials

“…These results indicated that the applied grid bias effectively obtained high-density networks and better junction properties at the C–Si interface when a-TiO 2 and a-Al 0.74 Ti 0.26 O 3 thin films were synthesized by the atomic phase CVD method. Jung et al proposed a high electron mobility transistor using a TiO 2 /SiN double-gate insulator [ 61 ]. Compared to the device with a SiN gate insulator, the device with dual-gate adiabatic showed improved gate controllability and channel electron density because of the high dielectric constant of TiO 2 .…”

Analysis for DC and RF Characteristics Recessed-Gate GaN MOSFET Using Stacked TiO2/Si3N4 Dual-Layer Insulator

“…We set the voltage at which the I D = 1 µA/mm as the breakdown voltage and observed the breakdown voltage of the device composed of Si 3 N 4 and TiO 2 and that composed of Si 3 N 4 to be 178 and 158 V, respectively. The device with the stacked TiO 2 /Si 3 N 4 dual-layer insulator had a larger breakdown due to the effective dispersion when a high voltage is applied; thus, it has a stronger ability to withstand the high heat generated by the high voltage from a device operation perspective [16].…”

“…set the voltage at which the ID = 1 μA/mm as the breakdown voltage and observed the breakdown voltage of the device composed of Si3N4 and TiO2 and that composed of Si3N4 to be 178 and 158 V, respectively. The device with the stacked TiO2/Si3N4 dual-layer insulator had a larger breakdown due to the effective dispersion when a high voltage is applied; thus, it has a stronger ability to withstand the high heat generated by the high voltage from a device operation perspective [16]. Figure 9a,b shows the current and unilateral gains based on frequency increase in the recessed-gate GaN MOSFET with the stacked TiO2/Si3N4 dual-and Si3N4 single-layer insulators, where cut-off frequency (fT) and maximum oscillation frequency (fmax) values were extracted at high frequency with and without SHE.…”

“…In our previous study, we compared the DC characteristics of recessed-gate MIS-HEMTs based on the variation of the Si 3 N 4 , TiO 2 insulator thickness and demonstrated that the application of an appropriate combination of two materials improves the device's DC electrical characteristics [16]. Further, detailed adjustments to the simulation parameters and models were performed, and it was examined that the results were observed to be the same in general.…”