Fabrication and characterization of solid-state nanopores using a field emission scanning electron microscope

Hung Chang, Birck Nanotechnology Center and School of Electrical and Computer Engineering, Purdue University,
Samir Iqbal, Birck Nanotechnology Center and School of Electrical and Computer Engineering, Purdue University
E A. Stach, Birck Nanotechnology Center and School of Materials Engineering, Purdue University
Alexander H. King, Birck Nanotechnology Center and School of Materials Engineering, Purdue University
Nestor J. Zaluzec, Electron Microscopy Center, Materials Sciences Division, Agronne National Laboratory
Rashid Bashir, Birck Nanotechnology Center, School of Electrical and Computer Engineering, Weldon School of Biomedical Engineering, and School of Mechanicl Engineering, Purdue University

Abstract

The fabrication of solid-state nanopores using the electron beam of a transmission electron microscope TEM has been reported in the past. Here, we report a similar method to fabricate solid-state nanopores using the electron source of a conventional field-emission scanning electron microscope FESEM instead. Micromachining was used to create initial pore diameters between 50 nm and 200 nm, and controlled pore shrinking to sub 10 nm diameters was performed subsequently during in situ processing in the FESEM. Noticeably, different shrinking behavior was observed when using irradiation from the electron source of the FESEM than the TEM. Unlike previous reports of TEM mediated pore shrinkage, the mechanism of pore shrinkage when using the FESEM could be a result of surface defects generated by radiolysis and subsequent motion of silicon atoms to the pore periphery.