Deposition and Characterization of Nanocrystalline Al_2O_3 Thin Films by DC Reactive Magnetron Sputtering

摘要

Alumina (Al_2O_3) thin films were deposited over glass and Si <100> 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 550°C 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.