INFRARED AND MORPHOLOGICAL-STUDIES OF HYDROGENATED ALN THIN-FILMS

Thin films of polycrystalline AlN and amorphous hydrogenated AlN (AlN:H) were prepared by ion beam reactive sputter deposition. The microstructures of these films were characterized by reflection absorption Fourier transform infrared spectroscopy (RAIR), scanning tunneling microscopy (STM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The microstructural characteristics of these nitride films were related to their adhesion properties. Polycrystalline AlN films are found to have poor adhesion on oxides and gold, but hydrogenated films have good adhesion. Hydrogenated AlN films contain AlN as the principal component and Al-N2 and NHx as minor species. The concentrations of the minor species depend on the amount of H-2 present in the sputtering gas mixture. Prolonged aging of AlN:H films in an ambient environment promotes surface hydrolysis and modifies adhesion properties.