Investigation of structure of AlN thin films using Fourier-transform infrared spectroscopy

Abstract

This study focuses on structural imperfections caused by hydrogen impurities in AlN thin films obtained using atomic layer deposition method (ALD). Currently, there is a severe lack of studies regarding the presence of hydrogen in the bulk of AlN films. Fourier-transform infrared spectroscopy (FTIR) is one of the few methods that allow detection bonds of light elements, in particular - hydrogen. Hydrogen is known to be a frequent contaminant in AlN films grown by ALD method, it may form different bonds with nitrogen, e.g. amino (–NH2) or imide (–NH) groups, which impair the quality of the resulting film. Which is why, it is important to investigate the phenomenon of hydrogen as well as to search for the suitable methods to eliminate or at least reduce its quantity. In this work several samples have been prepared using different precursors, substrates and deposition parameters and characterized using FTIR and additional techniques such as AFM, XPS and EDS to provide a comparative and comprehensive analysis of topography, morphology and chemical composition of AlN thin films.