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Abstract

During recent years, scanning probe microscopy (SPM) has become an essential tool in materials science. It does not only allow an ultimate analysis of the surface structure, but also unique procedures such as material deposition, initiation of chemical reactions, mechanical structuring as well as manipulation of atoms, molecules, and clusters. Practically important phenomena such as friction, adhesion, and surface diffusion can be studied on the microscopic scale.A review of results on several different subjects studied during the last years by application of scanning tunnelling microscopy (STM) and scanning force microscopy (SFM) is summarised below. Si(111) surfaces, the thermal stability of these clusters, and single electron tunnelling through these clusters: By application voltage pulses between tip and sample of a UHV-STM, clusters with a diameter between 3 and several hundred nanometers have been generated on Si(111) surfaces. The clusters are stable during 24 h and, at small clusters, Coulomb staircase effects have been observed. Local deposition of Al and Au clusters atMechanical structuring of gold surfaces and the measurement of surface self diffusion constants by detection of the decay of surface profiles: By nano-ploughing with an SFM, periodical grids have been produced on polycrystalline Au surfaces. From the decay of the profile amplitude as a function of the annealing time, 1,2 the surface diffusion constant and the activation energy for surface diffusion processes were derived according to the theory of Mullins. 3 Dynamics of gold cluster systems grown out of 10 nm thick gold films deposited on SiO x -surfaces of Si-wafers: Ostwald ripening processes 4,5 and the appearance of depletion zones have been observed by SFM. The size of the clusters and the cluster density have been measured as a function of annealing time in order to prove the growth laws.Temperature and time dependence of the topography of nanocrystalline Au: The growth of the grains and the determination of grain boundary root angles have been analysed with an SFM in air. Above 300°C annealing temperature, a fast grain growth was observed. The change of the mean grain diameter as a function of annealing time and temperature 2 was compared with the theory as discussed by Suryanarayana. 5,6 The structure of Al-cluster systems grown by the StranskiKrastanov mode at Si(111) surfaces: After deposition of 1-2 monolayers of Al at room temperature and subsequent annealing at 750 K, Al islands are grown forming the δ-phase as identified by SFM measurements. 7 Topography and magnetic analysis of (Fe/Mo) multilayer systems: For the first time layered structures could be analysed with an SFM by analysing the wall of a shallow crater produced by ion sputtering. The layered magnetic structure could also be detected by this method. At the untreated surface, the roughness has been measured as a function temperature. Cluster growth by Ostwald ripening processes was observed for annealing temperatures ≥ 500°C.Temperature dependence of the str...