The Effect of Depth on Fabrication of Nanopore using One-step Focused Ion Beam Milling for DNA Sequencing Application

We report the effect of depth on fabrication of nanopore on silicon substrate by utilizing one-step focused ion beam (FIB) milling. The conical shaped of nanopores were successfully fabricated by optimizing the milling parameters of FIB system. The milling depth, base diameter and tip diameter of the resulting nanopores were characterized using field emission scanning electron microscope (FESEM). The minimum diameter of the conical shaped nanopore was found to be 66.51 nm. Moreover, when aspect ratio is less than unity, the redeposited material will land on the tip of the nanopores and adhere at the sidewall for high aspect ratio. This result will be beneficial towards the new generation of nanopore-based DNA sequencing.