Development of microcones induced by contamination lithography

Abstract

The method of contamination lithography was applied for the generation and investigation of microcones and related topographies which occur during the ion bombardment of solids. One of the mechanisms for the development of microstructures under ion bombardment is the initial shadowing of the sample surface by micro particles. In contrast to the generally unintended deposition of such impurities, the proposed method allows the definite production of 3-dimensional carbonaceous contamination shields with adjustable height and extension, so that systematical studies of the development of the ion beam induced microcones and the behaviour of the surface topography under further ion beam exposure are possible. For deposition of the desired contamination shields a standard commercial scanning electron microscope was used. Pb single crystals have been prepared with contamination shields of 0.4 μ m height. Subsequent Ar +-ion bombardment was performed for different erosion depths and for ion incidence angles of 0°, 25° and 45° relative to the target normal. During oblique ion bombardment the target rotated around the normal. Cones, cylinders and double cones of micron size were produced under the different exposure conditions and investigated for different stages of development with respect to size and flank elevation angles.