Study on band gap and dispersion model of Al2O3 thin films with different oxygen flow rates by ion beam sputtering

Six groups of single-layer Alumina (Al2O3) thin films with different oxygen flow rate were prepared by ion beam sputtering. The oxygen flow rate changed from 0 sccm to 50 sccm with the interval of 10 sccm. The transmission spectrum, reflection spectrum and ellipsometric reflection spectrum of Al2O3 thin films were analyzed by cody-lorentz model inversion calculation. The surface roughness of six groups of samples was measured by white light interferometer. The effects of oxygen flow on band gap, Urbach band-tail absorption, deposition rate, surface roughness, deposition rate of Al2O3 thin films were studied. The experimental results showed that oxygen flow directly affects the band gap, Urbach tail absorption, deposition rate, surface roughness and deposition rate of Al2O3 thin films.