Macroscopically mechanical properties are dominated by a statistical distribution of defects with characteristic length scales like size and distribution of flaws in brittle fracture (100mm), or dislocation interdistance in metal plasticity (100nm). As dimensions are scaled down below the characteristic length, material properties become controlled by geometrical constraints. This includes physical device dimensions as well as microstructure length scales like grain size.

Conventional optical lithographic techniques that form the basis of integrated-circuit chip fabrication can already be used to create sub-100 nm features, but requires huge investments. We explore new nanostructuring strategies for metals based on electrochemical and charged particle beam lithography techniques. On the one hand, electron and ion beam induced deposition is an attractive nanofabrication tool due to its capability of depositing structures of metallic material with nanoscale control of both size and placement.

Novel research in nanomechanics and nanostructuring requires specialised instrumentation, not all of which is available commercially. The microanalysis group within the Laboratory for Mechanics of Materials and Nanostructures has

• glow discharge instruments which are used for (quantitative) chemical depth profiling with nanometer depth resolution and part per million level detection limits. We have both GD-OES and GD-TOFMS instruments.
• a Raman microscope, capable of also using the surface-enhanced and tip-enhanced Raman effects (SERS and TERS respectively). This can be used for stress mapping on a sub-micron spatial scale.
• a high spatial resolution Secondary Ion Mass Spectrometer (SIMS), integrated within a dual beam SEM-FIB instrument. This is used for chemical imaging (including depth profiles) on a smaller spatial scale than can be accessed by the glow discharge instruments.