On the thermal stability of nearly lattice-matched AlInN films grown on GaN via MOVPE

Abstract

Abstract The thermal stability of nearly lattice-matched AlInN films grown via metalorganic vapor phase epitaxy on GaN/sapphire is investigated. The structural and morphological changes of the AlInN layers, as determined by x-ray diffraction (XRD) and atomic force microscopy (AFM), are studied when systematically varying annealing times, temperatures, and ambients to gain a better understanding of the temperature limits of the AlInN films. The samples are annealed either in the growth chamber with the same conditions (gases, pressure, and flow rates) as the original growth conditions of the AlInN samples, or in the XRD under N2. In general, the surface of the AlInN changes at temperatures >850 °C under growth and N2 conditions mostly likely due to a loss of In as determined by AFM. However, the bulk crystal structure of the AlInN remains stable up to temperatures of 950–1050 °C (depending on ambient) as determined by XRD. These findings provide a helpful guide for future experiments involving high-temperatures (790–1050 °C) for subsequent or transition layers during epitaxial growth, and for fabricating device structures employing AlInN layers.