Abstract: Thermal oxidation processes on Al thin film were
studied. Aluminum was sputtered and oxidized in pure oxygen gas for 8 to 128
hours at various temperatures from RT to 473K. Composition of aluminum oxide was
analyzed by XPS and the electric characteristics of tunneling junctions which
have the oxide film as an insulator were also investigated. At first stage of
the oxidation, it is found that an amorphous is formed, although metallic
Al often remains in the film. When the oxidation temperature is high and the
oxidation time is long enough, the mixture phase changes to an amorphous single phase with the high
barrier height. The oxidation states at various stages were confirmed by
measuring dielectric constants of the junction. The high temperature and long
time oxidation brings to insulating layer, which
leads to a high resistivity junction with high breakdown voltage.
Keywords and phrases: aluminum thin film, thermal oxidation, tunneling junction.
