Surface topography development under energetic particle bombardment

The study encompasses the important factors in cone initiation on silver metal surfaces. The experimental data indicate the importance of surface contaminants on metal surfaces bombarded by energetic Xe atoms. The effect of contaminants was found to be more effective in initiating cones than the presence of asperities or irregularities. In the absence of diamond microparticles faceted or etch pits were observed instead of conical structures. In some cases isolated cones were observed due to the presence of bulk or isolated surface impurities. The process of initiation although similar to the "left standing" model, differs slightly on the basis that the impurities were only needed to initiate the cones to an optimum size. Once initiated the cones grow according to laws governing topography development, i.e first order theory, fusion of the neighboring cones into "supercones" and redeposition of sputtered materials.;Another factor which was investigated is the effect of mechanical stress in initiating surface topography. The presence of high mechanical stress, probably near breaking point of silver metal under study induced the formation of filament-like structures. The type, size and the population density of surface structures formed was found to be influenced by the magnitude of mechanical stress. Decreasing the magnitude of mechanical stress enhanced the formation of small densely populated cones. Similar effects were observed when mechanical stress was induced on chemically polished silver surfaces. At low mechanical stress levels faceted or etch pits were formed instead of low population density of cones observed in mechanically polished surfaces.;The study also included the use of 3-dimensional computer simulation to study the processes involved in shape and groove development of a cone. The 3-D computer program included experimental data points from silver semidynamic studies, calculated data from the literature of redeposition factors, sputtering yields, and enhancement factors. Overall the 3-D computer simulation offered some promise for further study probably involving more than one cone, and also including a fusion process as additional data points.