Micro electro-mechanical system design, fabrication and application for atomic force microscopy probe elasticity characterisation

Abstract

The work in this thesis is focused on characterising elastic behaviour of micro-cantilever probes found at the core of Atomic Force Microscopy (AFM) tools. It is an essential property to AFM force measurements, since interpretation of the cantilever deflection is directly related to the measure of the tip-sample force via its elastic conduct. It was demonstrated that the conventional micro-cantilevers can be well characterised using analytical and FE methods, together with the ready developed tools and experimental techniques, which formed the insights for the design practices used in further and more complex structure development efforts. However, this project’s emphasis was placed on assessment of non-traditional AFM cantilever structures that are not supported by the said methods, and hence necessitated in the conceptualisation and development of a dedicated micro electro-mechanical system (MEMS) solution. The sensitive force and elasticity measurement device, based on metal film resistive strain sensing, was realised using semiconductor and MEMS fabrication approaches in the James Watt Nanofabrication Centre, allowing the desired performance to be achieved with an in-house process optimisation. The functional MEMS tool paired with bespoke instrumentation was then employed to characterise a range of commercial cantilevers as well as non-standard probes consisting of complex composition multi-structures and non-linear elasticity, providing novel insights into their elastic character

    Similar works