SPM nanolithography of Mg-Hydroxyde on Siloxane Layers and Finite Element Analysis of Cantilever Electromechanical Deflection

In the first part of the contribution the author shows that by using an atomically flat magnesium hydroxide/siloxane layer it is possible to both perform nanoindentation and nanodeposition with a scanning probe microscope. The removal of this kind of material is well-controllable and can be accomplished either by applying a positive voltage to the tip or to mechanically scratch the surface in contact mode without any voltage assistance. These results can find applications in several areas, such as, in surface self-assembly and nanopatterning of biomolecules; nanolithography and surface scratching for nanomarkers; nanomanipulations for electrical and mechanical studies; relocations of nanoparticles for electronic, magnetic or optical devices applications; dissections or alignement of molecules for life science and polymer research, bio-nanotechnology and biosensors development. The second part of the contribution is dedicated to SPM investigation of electrostatic forces at the nanoscale, that is of fundamental importance for the development of nanotechnology, since these confined forces govern many physical processes on which a large number of technological applications are based. In this work, in order to quantify the EFM cantilever/tip-sample interaction, we present a 3D static Finite Element Analysis (FEA) of the electro-mechanical interaction between conductive probes and samples by using a multiphysics approach with iterative solvers. The simulation was then compared with experimental data obtained in a EFM. Real geometric dimensions and shapes of the probe have been reproduced. Commercial rectangular and triangular shaped cantilevers with integrated single crystal tips for SPM were modelled. The simulation allowed to discriminate between force components due to specimen surface potential and probe geometrical constraints, such as: 1) tip-apex geometry, 2) cone-pyramid lateral surface and 3) cantilever shape. Unstructured meshes containing tetrahedral elements have partitioned the large scale factor geometries, from hundreds of microns of cantilever’s length down to some nanometers of tip’s radius of curvature. In addition, a Focused Ion Beam (FIB) was used to modify commercial probes in order to localize the conductive layer at the tip-apex or at its sides. The simulated curves were found to be very useful to deduce the regime where a single component between tip-apex, lateral surface and cantilever dominates, and further to estimate the spatial resolution and electrical sensitivity of EFM.