Deposition and Characterization of Nanocrystalline Al<sub>2</sub>O<sub>3</sub> Thin Films by DC Reactive Magnetron Sputtering

Abstract: Alumina (Al2O3) thin films were deposited over glass and Si substrates by DC reactive magnetron sputtering at an oxygen partial pressure of 0.03 Pa. The presence of aluminium and oxygen was confirmed using x-ray photoelectron spectroscopy and the films were found to be nearly stoichiometric or oxygen rich at a sputtering power of 70 W and 60 W, respectively. The as-deposited films were found to be amorphous. Subsequent annealing experiments in vacuum revealed that crystallisation started at 550oC and increased thereafter at higher annealing temperatures for those films deposited at a sputtering power of 70 W. The topography of the as-deposited and annealed films was analyzed by Atomic force microscopy and a progressive increase in the rms roughness of the films was observed with increase in the annealing temperature and the results are discussed