A large-area pulsed laser deposition (PLD) technique was used to uniformly grow tantalum pentoxide (Ta2O5) films on silicon wafers of 75 mm diameter. A KrF excimer laser beam was focused onto a 90 mm diameter Ta2O5 target to induce its ablation in oxygen gas ambient. The large-area coverage was obtained by rastering the laser beam over the radius of the rotating target, while the substrate was rotated simultaneously.
The tantalum oxide films were characterized in terms of uniformity of thickness, composition, structure, and optical properties across the substrate. Average deviations typically below 1% were achieved in thickness, composition, indices of refraction and optical energy band-gap. Identical X-ray diffraction spectra were obtained at the center, middle of radius and edge of the wafers.