REACTIVE SPUTTERING OF TA UNDER GRADIENT OXYGEN-PRESSURE

The reactive deposition process of TaO(x) thin films onto a substrate surface under a gradient of oxygen pressure in dc magnetron sputtering was studied. By assuming that Ta and O2 react on the Ta target and th e glass substrate surface, the dependence of film characteristics on t arget current and the position on the substrate surface was explained. Transparent films were obtained under the condition: average total pr essure P(Ar+O2)=5 X 10(-3) Torr, average oxygen pressure P(O2)=6 X 10( -4) Torr, target current density < 0.042 A/cm2, deposition rate < 830 angstrom/min. For these conditions, about 73% of Ta atoms deposited on the substrate were oxidized on the target surface and the rest, on th e substrate surface. The oxygen flux onto the substrate should be 40 t imes larger than the tantalum flux to obtain stoichiometric tantalum o xide films.