Fabrication of silicon nanopillars containing polycrystalline silicon/insulator multilayer structures

A new approach to three-dimensional nanostructures is discussed-with the goal of-fabricating vertical, ultrasmall tunneling junctions suitable for single electron devices. Pillars consisting of multiple layers of polycrystalline silicon (polysilicon) (similar to 10 nm thick) and silicon nitride (similar to 2 nm thick) were laterally oxidized. The fabrication of vertically stacked silicon nanoislands, with dimensions on the order of 10 nm in all three directions, connected by thin silicon nitride layers, is demonstrated. The saturation of the polysilicon core diameter during the lateral pillar oxidation process is clearly observed, confirming the self-limiting effect for polysilicon pillars. This approach allows the fabrication of three-dimensional nanostructures using conventional silicon processing equipment. (C) 1997 American Institute of Physics.