Ti0.5Al0.5O-Dielectric AlGaN/GaN/Si Metal-Oxide-Semiconductor Heterostructure Field-Effect Transistors by Using Non-Vacuum Ultrasonic Spray Pyrolysis Deposition

Abstract

This work investigates a Ti0.5Al0.5O-dielectric Al0.26Ga0.74N/GaN metal-oxide-semiconductor heterostructure field-effect transistor (MOS-HFET) grown on a Si substrate, prepared by using a non-vacuum ultrasonic spray pyrolysis deposition (USPD) technique. High dielectric constant (k) was characterized to be 29.1 for a 20-nm thick Ti0.5Al0.5O. Hooge coefficient (αH), low-frequency noise spectra (1/f), high/low frequency capacitance-voltage (C-V), pulse I-V measurements were also performed to investigate the improved passivation and insulation of the MOS-structure. The present MOS-HFET design has exhibited superior improvements of 23% in maximum drain-source current density (IDS, max), 25.1% in drain-source saturation current density at VGS = 0 V (IDSS0), 46.3% in two-terminal off-state gate-drain breakdown voltage (BVGD), and 65% in three-terminal drain-source breakdown voltage (BVDS), as compared to a reference Schottky-gate HFET device. Enhanced high-frequency, power, and high-temperature performances up to 450 K are also studied.