OXIDATION-KINETICS OF METAL-FILMS AT 300-K STUDIED BY THE PIEZOELECTRIC QUARTZ CRYSTAL MICROBALANCE TECHNIQUE

The oxidation kinetics of metal films of lanthanum, titanium, hafnium, vanadium, tantalum, chromium, manganese, iron, nickel and aluminium were studied with a quartz crystal microbalance at 35-degrees-C and O2 pressures between 10(-3) and 10(5) Pa for exposure times ranging from 1 to 10(4) min. In the initial stage of the reaction (less than 2 min) a large amount of oxygen is absorbed in a very fast process and oxide scales are formed with a thickness between 1 and 10 nm. This quantity depends on the metal under consideration and in some cases (lanthanum, titanium, vanadium, tantalum, aluminium) strongly also on O2 pressure. In the subsequent oxidation process (10 to 10(3) min) smaller amounts of O2 are absorbed at a logarithmic growth rate of differing magnitude for various metals.