2. Local Oxidation Using Dynamic Force Mode: Toward Higher Reliability and Efficiency

Local oxidation by scanning probe microscopy (SPM) is used extensively for patterning nanostructures on metallic, insulating, and semiconducting thin films and substrates. Numerous possibilities for refining the process by controlling charge density within the oxide and shaping the water meniscus formed at the junction of the probe tip and substrate have been explored by a large number of researchers under both contact mode (CM) and dynamic-force mode (DFM) conditions. This article addresses the question of whether or not the oxide growth rate and feature size obtainable by each method arise from distinctly different kinetic processes or arise simply because charge buildup and dissipation evolve over different time scales for these two cases. We report simultaneous oxide-volume and current-flow measurements for exposures performed by CM and DFM and then go on to discuss the practical realization of enhanced reliability and energy efficiency made possible by a better understanding of the relation between oxidation time and ionic diffusion using DFM.