Sub-10 nm Fabrication of Large Area Periodic Nanopillars

Here we present a large-area fabrication technique that is capable of producing size-tunable periodic silicon nanopillar arrays with sub-10 nm resolution. Our approach is to transfer the patterns created by nanosphere lithography into silicon substrates, forming nanopillar arrays and modify the size, shape and height of nanopillar arrays by various etching schemes. Introduction To construct nanostructures with high degree of control, electron beam lithography is the most commonly used technique. However, the generation of secondary electrons during electron bombardment makes it difficult to pattern with sub-10-nm resolution. It is also inefficient to employ electron beam lithography for large-areas production because it is a sequential patterning technique. Scanning probe based lithographic techniques has also been used to pattern nanostructures with very high degree of control. However, it is very time consuming for scanning probe based lithography to create large area patterns at the nanometer scale. It has been reported recently that large-area periodic nanostructures can be obtained by transferring the patterns formed by the self-assembled nanospheres into silicon substrates forming nanopillar arrays and replicating the nanostructures using nanoimprint lithography. Since the size of silicon nanopillars can be trimmed by oxidation and etching processes, this approach provides an excellent way to produce size controllable nanostructures. In this paper, we report a simple fabrication process for producing large-area, size-tunable, periodic nanopillar arrays with lateral resolution smaller than 10 nm.