Fabrication of densely packed, well-ordered, high-aspect-ratio silicon nanopillars over large areas using block copolymer lithography

The fabrication process for well-ordered nanopillars over large substrate areas, which are taller than 100 nm, have aspect ratios as high as 10 : 1 and occur with a periodicity of less than 35 nm is described. Various unique aspects of the materials and processing techniques enabled key features of the nanostructures: block copolymer lithography facilitated the small periodicity and the well-ordered arrangement of the pillars, a unique lift-off technique overcame potentially prohibitive lift-off problems, and a highly selective and anisotropic NF3 based reactive ion etching achieved the final nanopillar structure. The specifics of the processing can be suitably modified to obtain pillars with different physical characteristics.