Crystallization of tantalum oxide formed by PLD

Tantalum oxide films were deposited on stainless steel by KrF excimer laser ablation of Ta and beta-Ta2O5 plates at an oxygen pressure of I mPa-200 Pa. The effects of oxygen pressure on the deposition rate and chemical composition of the films were systematically investigated. The O/Ta atomic ratio and deposition rate increased with increasing oxygen pressure. At a pressure of 5 Pa, the O/Ta atomic ratio was nearly equal to the stoichiometric atomic ratio of Ta2O5. Although films deposited at room temperature at an oxygen pressure of 10 mPa-200 Pa were amorphous, the film deposited at 1 mPa was oriented to Ta(110). Crystallized delta-Ta2O5, films were obtained by annealing at 973 K for 3.6 ks under vacuum. There was no difference between the Ta and beta-Ta2O5 targets in the pressure required for a stoichiometric film or the annealing temperature required for a crystalline film. Films deposited on a heated substrate were crystallized at a temperature approximately 300 K lower than the annealing temperature required for a crystalline film. (C) 2002 Elsevier Science B.V. All rights reserved.