Fabrication of sub-20 nm nanopore arrays in membranes with embedded metal electrodes at wafer scales†
We introduce a method to fabricate solid-state nanopores with sub-20 nm diameter in membranes with embedded metal electrodes across a 200 mm wafer using CMOS compatible semiconductor processes. Multi-layer (metal–dielectric) structures embedded in membranes were demonstrated to have high uniformity (±0.5 nm) across the wafer. Arrays of nanopores were fabricated with an average size of 18 ± 2 nm in diameter using a Reactive Ion Etching (RIE) method in lieu of TEM drilling. Shorts between the membrane-embedded metals were occasionally created after pore formation, but the RIE based pores had a much better yield (99%) of unshorted electrodes compared to TEM drilled pores (<10%). A double-stranded DNA of length 1 kbp was translocated through the multi-layer structure RIE-based nanopore demonstrating that the pores were open. The ionic current through the pore can be modulated with a gain of 3 using embedded electrodes functioning as a gate in 0.1 mM KCl aqueous solution. This fabrication approach can potentially pave the way to manufacturable nanopore arrays with the ability to electrically control the movement of single or double-stranded DNA inside the pore with embedded electrodes.