Investigation of Ta2O5 and TaSixOy thin films obtained by radio frequency plasma assisted laser ablation for gate dielectric applications

Pulsed laser deposition was employed for the growth of tantalum oxide and tantalum silicate thin films. Ta2O5 thin films were obtained following the ablation of a metallic Ta target by the 3rd (355 nm) and 4th (266 nm) harmonics of a Nd:YAG laser. For the deposition of TaSixOy thin films, a composite target consisting of Si (25%) and Ta (75%) sectors was ablated and the resulted material was collected on platinum coated silicon substrates. The influence of different experimental parameters, such as substrate temperature (from 200 to 400 °C) and laser wavelength, on the morphology and electrical properties of the thin films was investigated. We find that although the addition of the RF plasma to the PLD procedure increases surface roughness, it improves the electrical properties of the resulting structures, leading to lower leakage currents and wider range of the electric field.