A two-step growth route of ternary aluminium doped zirconium oxide film on silicon

Abstract

Abstract Co-sputtering and post-sputter oxidation were incorporated as a two-step growth route for the formation of ternary aluminium doped zirconium oxide (AlxZryOz) films on silicon (Si) substrate using Al-Zr alloy film as the template film. Post-sputter oxidation at 400, 600, 800, and 1000\u202f°C has transformed the amorphous as-deposited Al-Zr film to crystalline AlxZryOzfilms. A mixed monoclinic-tetragonal phase of AlxZryOz films was formed at 400 and 600\u202f°C, while above which, tetragonal phase was obtained. The increase of oxidation temperature has also encouraged the formation of aluminium zirconium silicate (Al-Zr-Si-O) interfacial layer (IL), owing to an increase in the adsorption and diffusion of oxygen molecules from the ambient. The presence of excess oxygen in the film oxidized at the highest temperature (1000\u202f°C) has translated into the formation of oxygen interstitials residing in the lattice, which have induced mid-gap states at the band gap of the film. As a result, a degradation in leakage current density-voltage (J-V) characteristic was obtained and the corresponding structural, optical, and capacitance-voltage characteristics were presented in comparison to the films oxidized at lower temperatures.