| Pulsed laser deposition (PLD) is a versatile technique for the deposition of a variety of thin films. A major problem of PLD is the generation of microsized debris particles during laser ablation process and these debris particles contaminate the thin film. In this thesis, a novel technique for debris particle reduction is studied. A 50cm-long straight magnetic field up to 2 kilogauss is used to capture and guide carbon plasmas produced by 248nm (50mJ, 20ns) and 266nm (5mJ, 10ns) laser pulses along the field to the substrate to be coated, while the debris particles are not guided and are allowed to expand freely. In addition, the debris particle velocities are much lower than the ion velocities. In principle, this allows a mechanical shutter to be used to further reduce the number of debris particles reaching the substrate to be coated. By using ion probes and Quartz Crystal Microbalance (QCM), the transport efficiency of the plasma and its dependence on the guiding magnetic field are studied. A Monte-Carlo simulation code based on single-particle theory and a 3D ADI magnetohydrodynamic (MHD) code based on an earlier version are used to simulate the expansion of laser-generated plasma in a magnetic field. Our experiments and simulation results indicate it is feasible to use a straight magnetic field to transport a carbon plasma with efficiencies >40% for the parameters studied in this thesis. |
