Multiscale nanostructuring of Si surfaces combining top-down and bottom-up techniques

Surface patterning is of tremendous importance in many technological fields with features sizes ranging from nanometers to millimeters. There are different patterning techniques that generally can be assigned to the top-down and bottom-up approaches. One bottom-up method for the generation of self-organized nanostructures is low-energy ion beam erosion. However due to the stochasticity of the process there is a lack of large scale ordering of nanostructures and of positional control. Here results on self-organized nanostructuring of pre-patterned Si surfaces will be presented. The idea is to combine the top-down technique for pre-patterning of surfaces followed by the ion beam induced self-organization process. Due to the periodicity, shape and lateral ordering of pre-patterns an improved ordering, and an exact positional control of nanostructures is achieved. The method allows also for the formation of new structures and patterning of more complex surfaces like curved one or more difficult geometries are possible. The pre-patterned substrates are fabricated by various lithographic techniques in combination with etching techniques for structure transfer. Depending on the shape of the pre-patterned structure different results are obtained. Furthermore, using the imprint technique inverse pre-patterns (e. g. pits-holes) are used to study the self-organization process.