Fabrication of symmetric sub-5 nm nanopores using focused ion and electron beams

Nanopores fabricated in solid-state membranes have previously been used for the rapid electrical detection and characterization of single biopolymer molecules. Various methods for producing solid-state nanopores have been reported, but fabricating nanopores of desired sizes controllably is still challenging. Here we report a fabrication technique which uses a focused ion beam (FIB) system to engineer nanopores precisely. This technique provides visual feedback over the formation process. The present method can produce highly symmetrical nanopores with diameters smaller than ∼5nm and can be used to create an array of multiple nanopores simultaneously. In addition, nanopores produced using the focused ion beam sculpting technique can be tailored down to less than 1nm in diameter using high-energy electron radiation.