Nanopore Formation via Tip-Controlled Local Breakdown Using an Atomic Force Microscope

The dielectric breakdown approach for forming nanopores has greatly accelerated the pace of research in solid-state nanopore sensing, enabling inexpensive formation of nanopores via a bench top setup. Here the potential of tip-controlled local breakdown (TCLB) to fabricate pores 100× faster, with high scalability and nanometer positioning precision using an atomic force microscope (AFM) is demonstrated. A conductive AFM tip is brought into contact with a silicon nitride membrane positioned above an electrolyte reservoir. Application of a voltage pulse at the tip leads to the formation of a single nanoscale pore. Pores are formed precisely at the tip position with a complete suppression of multiple pore formation. In addition, the approach greatly accelerates the electric breakdown process, leading to an average pore fabrication time on the order of 10 ms, at least two orders of magnitude shorter than achieved by classic dielectric breakdown approaches. With this fast pore writing speed over 300 pores can be fabricated in half an hour on the same membrane.