Novel nanofabrication based on wet nanocoating.(1)- Fabrication of sub-20 nm line array e

We report herein fabrication of arrays of 20 nm silica wall with high aspect ratio via photolithography and the surface sol-gel process. The photolithographycally-fabricated line template on silicon wafer was coated with silica nanolayer by the surface sol-gel process, and the topmost portion of the silica layer and the template was successively removed by CHF₃ and oxygen plasma treatment in this order to leave the sidewall of the silica layer on the substrate. The width of as-prepared wall depended on the cycle of the surface sol-gel process, and the thickness of silica wall was only 8 nm at 30 cycles. The height/width ratio of the wall is surprisingly high compared to that of the current lithography processes. The reported method is simple, practical and cost-efficient, and it opens a gateway to further miniaturization of nanostructures.