Nanopore formation in TiN membranes by the focused electron beam of a transmission electron microscope

The authors fabricated 2-nm nanopores in metallic TiN membranes with and without a SiNx layer using the highly focused electron beam (e-beam) of a transmission electron microscope. Nanopore evolution in TiN membranes was observed as a function of e-beam exposure time at e-beam energies of 200 and 300 kV. To investigate the mechanism of nanopore drilling in TiN membranes, plots of nanopore diameter against exposure time were converted to characteristic contrast curves of normalized drilling volume versus electron dose. The curves indicated that nanopore drilling in TiN metallic membranes using a high-energy focused e-beam is governed by direct atomic displacement or surface sputtering by elastic scattering between electrons and stationary atoms. The sputtering energy of TiN is about 9 eV. (C) 2015 American Vacuum Society.