Growth of quaternary InAlGaN barrier with ultrathin thickness for HEMT application

摘要

Quaternary InAlGaN barriers with thickness of 7 nm for HEMT application were grown on 3-inch semi-insulating 4H-SiC substrates by metal organic chemical vapor deposition (MOCVD). Focused on growth mechanism of the InAlGaN barrier, the surface morphology and characteristics of InAlGaN/AIN/GaN heterostructures were studied with different growth parameters, including the temperature, Al/Ga ratio and chamber pressure. Among the as-grown samples, high electron mobility is consistent with smooth surface morphology, while high crystalline quality of the quaternary barrier is confirmed by measurements of Photoluminescence (PL) and Mercury-probe Capacity-Voltage (C-V). The recommended heterostructures without SiN passivation is characterized by mobility of 1720 cm(2)/(V.s), 2DEG density of 1.71*10(13) cm(-2), sheet resistance of about 210 Omega/rectangle with a smooth surface morphology and moderate tensile state, specially applied for microwave devices. 2018 Elsevier Ltd. All rights reserved.