AFM-based nano-machining: developing and validating a novel modelling approach for effective process implementation in nanotechnology applications

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Although photolithography or scanning beam lithography are techniques widely used for the fabrication of devices with nanoscale features, a drive still exists to explore alternative and complementary nanoscale manufacturing processes, particularly for supporting the development of proof-of-concept devices that integrate 3D nano-structures. This is due to the fact that conventional nanofabrication technologies rely on capital-intensive equipment in addition to being restricted in the fabrication of true 3D features and in the range of processable materials. Besides, there are also increased concerns over their environmental friendliness as they are energy and resource intensive and generate significant waste. One candidate nano-manufacturing process that may help address these limitations, particularly during the development stages of nanotechnology-enabled devices, relies on mechanical machining with the tip of an Atomic Force Microscope (AFM) probe. In particular, material removal operations on the nanoscale can be achieved as a result of using the AFM probe tip as a "nano-cutting tool". However, it is currently not possible for AFM practitioners to determine the required input process parameters, in terms of load to be applied by the tip and the cutting direction to be followed, for achieving specific groove dimensions without completing experimental trial-and-error campaigns first. For this reason, this project aims to implement a novel modelling approach of AFM-based nano-machining such that, given a set of input parameters, it will be possible for a user to predict the expected geometry of a machined groove, and vice versa. To achieve this overall aim, the project will develop and validate a new coupled SPH-FE (i.e. Smooth Particle Hydrodynamics - Finite Elements) model of the AFM tip-based nano-machining process. In addition, to ensure that such process modelling is based on reliable data, the project proposes to adopt novel experimental characterisation techniques to extract the mechanical properties of a workpiece material, which are specifically relevant for nanoscale cutting. Finally, the project also aims to demonstrate the increased potential of this nano-manufacturing process, when applied with the proposed modelling approach, for the development and implementation of nanotechnology applications through two lab-based demonstrators.