Primary-ion-beam deposition system for compound films

A deposition system for forming thin films by using two kinds of low-energy ion beams has been developed. By simultaneous irradiation with mass-separated Ta+ ion beam and oxygen ion beam, pure and stoichiometric Ta2O5 thin films were obtained at room temperature. The leakage current of the 30 nm thick Ta2O5 film at 500degC annealing was 7.3x10-7 A/cm2 at -5V applied voltage. Thin films of TaOx, WOx, and MoOx were deposited on Si substrates. The silicon contaminations in these films were closely correlated to the beam energy. The best condition of the beam energy can be predicted by the standard free energy of film formation. (author)