Radicals transport modelling in NANOJET

NANOJET (Nanonozzle Plasma Jet Microfabrication Technology) based on scanning micro/nano-nozzle is a competitive candidate for high-resolution direct nano-structuring of different materials. In this device, electrically neutral radicals created in plasma discharge are transported through a small tapered capillary (or nozzle). A short distance between the nozzle and treated surface allows the localized chemical interaction. A description of free radicals transport through a high aspect ratio hollow tip and localized etching and high etching rates without ion bombardment are demonstrated in this work. A Monte Carlo (MC) based simulation model is used to study the transport and kinetic properties of atomic oxygen gas flow through the finite length cylindrical nozzle with different aspect ratios. The general aim of these investigations is to determine and optimize the radicals transport and optimal etching capability. The MC-simulations are compared with detailed experimental measurements, carried out for different nozzle sizes, etching rates, and distances between the nozzle outlet and the sample. To explore the influence of the oxygen gas flow kinetic properties on the etching parameters, the oxygen atoms transmission is simulated for a variety of the nozzle aspect ratios. This article presents the fundamental considerations and the experimental proofs of the outlined nanofabrication technique.