Proximal probe-based fabrication of nanometer-scale devices

We describe a simple and reliable process for the fabrication of nanometer-scale structures by using the local electric field of 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. Alternately, this process of anodic oxidation can be used to oxidize completely through thin metal films to make nanometer-scale lateral metal-oxide–metal tunnel junctions.