Plasma enhanced pulsed laser deposition

This thesis introduces a novel deposition technique, Plasma-Enhanced Pulsed Laser Deposition (PE-PLD) that attempts to overcome limitations in traditional PLD by combining it with a background oxygen RF plasma instead of a neutral gas. Advantages of this novel technique for the deposition of metal-oxide films include, the use of simple, pure metal targets instead of metal-oxide composite targets and the lack of the necessity for substrate heating and post-annealing to obtain high-quality films. The feasibility of this method was studied both numerically and experimentally. Numerical simulations of the laser ablation process and an Inductively Coupled Plasma (ICP), i.e. the oxygen RF plasma, using different 2D hydrodynamic codes, found that the densities of the Cu plume and ICP were similar in front of the substrate, allowing the necessary interaction between them to oxidize the Cu and deposit a CuO film.

Time-resolved optical emission spectroscopy provided electron temperatures and densities that were used to benchmark the modelling results as well as provide some insight into the process of slowing down of the plume due to the background gas. Also, the assumption of Local Thermodynamic Equilibrium (LTE), commonly used in these diagnostic techniques, was investigated and found to not be strictly full filled for most of the ablation process, meaning that further investigations are needed to confirm the validity of these diagnostics. Finally, copper oxide thin films were deposited using PE-PLD. Analysis of the composition showed that high-quality films could be formed and that at a low oxygen pressure stoichiometric, polycrystalline CuO was formed, while at a higher pressure stoichiometric, polycrystalline Cu2O was deposited.