Proximal probe-based fabrication of nanostructures

We describe a simple and reliable process for the fabrication of nanometre-scale silicon structures by using the local electric field of a proximal probe tip (either an STM or a conducting tip atomic force microscope) to write surface oxide patterns by local anodic oxidation. These oxide patterns can be used as masks for selective etching to transfer the pattern into the substrate. This process has been used to fabricate side-gated Si field effect transistors with critical features as small as 30 nm. Alternatively, this process of anodic oxidation can be used to oxidize completely through thin metal films to make lateral metal-oxide-metal tunnel junctions.