Effects of Growth Temperature on Structural and Electrical Properties of InAlN/GaN Heterostructures Grown by Pulsed Metal Organic Chemical Vapor Deposition on c-Plane Sapphire

Abstract

The authors report the effects of growth temperature on the structural and electrical properties of InAlN/GaN heterostructures, which were grown on c-plane sapphire substrates by pulsed metal organic chemical vapor deposition (PMOCVD). High resolution X-ray diffraction (HRXRD) and atomic force microscopy (AFM) measurements indicate that the quality of InAlN barrier is strongly dependent on the growth temperature. It is observed that the indium composition and surface root-mean-square (rms) roughness value of InAlN barrier decrease with increasing the growth temperature, and a nearly lattice-matched InAlN/GaN heterostructure with a smooth surface is obtained at 710 °C. As a consequence, the variation of structural properties of InAlN barrier influences the electrical properties of InAlN/GaN heterostructures, and high electron mobility in excess of 1400 cm2 V-1 s-1 is achieved at an optimized growth temperature window of InAlN barrier layer between 710 and 730 °C.