Tomographic imaging using conductive atomic force microscopy

Conductive atomic force microscopy was used to image permalloy nanostructures embedded in Al2O3. Two layers of permalloy nanostructures embedded in Al2O3 were fabricated in a stacked manner using nanosphere lithography and electron beam evaporation. Bias dependence conduction of the bottom and top layers of the permalloy nanostructures was demonstrated. A simple phenomenological model based on thermionic emission, direct tunnelling and Fowler-Nordheim tunnelling was used to explain the experimental findings. When applied to Co-HfO2 granular films, the technique enabled 3D reconstructed images of the films to obtain grain size information in a non-destructive manner. This relatively simple and cost-effective technique has the potential to be developed to image nanostructures and devices tomographically.