Processing of New Functional Material Using Electron Beam Excited Plasma

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Pulsed laser beams irradiated onto the target surface produce plasma containing atomic scale particles and droplets of various sizes. These emitted particles travel in the direction of the target normal. Various useful engineering practices can be envisaged by depositing these particles on the surface of a substrate. The expanding plasma is usually forward peaked and the degree of forward peaking primarily depends on the dimensions of the laser beam on the target surface, the laser energy density and wavelength and pulse duration. These factors determine the film uniformity and homogeneity that are of significant importance in manufacturing. In this research at first, numerical calculations that predict the deposit thickness distribution were set based on hydrodynamical model. Then, the results were compared with experimental results obtained by irradiating a focussed pulse laser beam onto the surface of an aluminum tape target. The thickness distributions of the deposited film are mea … More sured in the vertical and horizontal directions. Our experiments and numerical calculations show close resemblance. Based on the results of the thickness distributions, practical recipes relevant to deposition practice are presented. Here are the conclusions drawn from the experimental and predicted simulation of this research.1. The deposit area produced from a high aspect ratio irradiated target area is narrow in the direction parallel to the longer side and wide in the direction parallel to the shorter side of the irradiated area. The degree depends on the value of the aspect ratio of the irradiated target area.2. The deposit area produced from a spot, square, irradiated target area has the same dimension in all directions. And the deposit area produced from a square irradiated target area is wider than the deposit area produced from a high aspect ratio irradiated area.3. Thus, the deposition rate of high aspect ratio substrates can be greatly improved by simply focussing the laser beam into a high aspect ratio irradiated area. The thickness uniformity can be obtained by rotating the substrate while scanning along the required deposition area. Less