Oxidation rates of aluminium nitride thin films: effect of composition of the atmosphere

Abstract

This paper presents an analysis of thermal oxidation kinetics for Aluminium nitride (AlN) epitaxy layers using three methods: dry, wet and mixed. The structures thus obtained were examined by means of scanning electron microscope, energy-dispersive X-ray spectroscopy, spectroscopic ellipsometry and secondary ions mass spectroscopy. On the basis of the investigation results, a model of layer structure after oxidation was proposed, the thickness of the layers was assessed and the refractive indices for particular layers were determined. The modelling results prove that AlN thermal oxidation in dry oxygen follows the logarithmic law, wet oxidation follows the parabolic law, whereas mixed oxidation follows the linear law.