Nanopore Array Fabrication on Bulk Silicon and Silicon Membranes by Electrochemical Etching

Abstract: In this project, nanopore arrays have been fabricated on bulk silicon and on silicon membranes by electrochemical etching. First, the surface of bulk silicon and silicon membranes have been patterned by photolithography and then invert pyramidal pit arrays have been formed by KOH etching. To fabricate nanopore arrays, bulk silicon and silicon membranes with the inverted pyramidal structure were electrochemically etched with backside illumination and by breakdown methods, respectively. Pore morphology was then characterized by scanning electron microscopy (SEM). On bulk silicon, etching by backside illumination did not form promising nanopore arrays; while arrays of nanopores with ~8 nm in diameter have been fabricated to a depth of 18 μm by tuning the applied breakdown bias. On silicon membranes, arrays of nanopores with 18±4 nm diameter have been etched through the membranes with the buried oxide remaining on the backside using the breakdown method.