Fabrication of InAlGaN/GaN High Electron Mobility Transistors on Sapphire Substrates by Pulsed Metal Organic Chemical Vapor Deposition**Supported by the National Science and Technology Major Project of China under Grant No 2013ZX02308-002, and the National Natural Sciences Foundation of China under Grant Nos 61574108, 61334002, 61474086 and 61306017.

Abstract

Nearly lattice-matched InAlGaN/GaN heterostructure is grown on sapphire substrates by pulsed metal organic chemical vapor deposition and excellent high electron mobility transistors are fabricated on this heterostructure. The electron mobility is 1668.08 cm2/V·s together with a high two-dimensional-electron-gas density of 1.43 × 1013 cm−2 for the InAlGaN/GaN heterostructure of 20 nm InAlGaN quaternary barrier. High electron mobility transistors with gate dimensions of 1×50 μm2 and 4 μm source-drain distance exhibit the maximum drain current of 763.91 mA/mm, the maximum extrinsic transconductance of 163.13mS/mm, and current gain and maximum oscillation cutoff frequencies of 11 GHz and 21 GHz, respectively.