Study of laser plasmas in straight magnetic fields for thin film deposition

Abstract

Summary form only given. Pulsed Laser Deposition is a versatile technique for depositing a variety of materials in thin films form. One complication with pulsed laser deposition is the inclusion of micron and submicron size debris particles from the source materials. These particles arise from the release of solid material and liquid droplets from the shock wave produced by the laser produced plasma. An additional issue arising in the deposition process is the rapid fall off in coating flux with distance from the plasma source point. Thus if high coating rates are desire, the substrate must be located close to the plasma source. In this paper the guiding of plasmas produced by nanosecond ultraviolet laser pulses using straight solenoidal magnetic fields has been studied as a mean of giving a low-debris, controlled deposition source for the production of thin films. Experimental study on the guiding efficiency of the coating flux at various magnetic field strength, using Langmuir probes and quartz crystal monitor has been carried out. The transport of the ionization portion of the laser plasma was measured by arrays of Langmuir probes and the total coating flux including neutrals was measured by a quartz crystal monitor. In addition to the magnetic field strengths, the orientation of the target and the repetition rate of the laser also affect the transport efficiency. These results were presented and compared to predictions of plasma guiding using numerical plasma simulation models.