Helium focused ion beam irradiation with subsequent chemical etching for the fabrication of nanostructures

Abstract

In this paper we demonstrate a nanofabrication technique based on local ion irradiation of silicon dioxide with a focused helium ion beam. The wet etching of silicon dioxide irradiated with a focused helium ion beam is described in a two-dimensional case both numerically and experimentally. We suggest a model for the etching process based on the distribution of ion induced defects in the irradiated material. The profile of the surface of the etched silicon dioxide is simulated and compared with the results from scanning electron microscopy. Fabrication of a suspended nanostring with a diameter of less than 20 nm by means of etching ion-irradiated material is demonstrated.

Helium Ion‐Assisted Wet Etching of Silicon Carbide with Extremely Low Roughness for High‐Quality Nanofabrication

“…[27][28][29] Over the recent decades, this IBEE technique has undergone significant advancements owing to improvements in processes and equipment. [30][31][32][33][34] The basic concept of HIBEE is to artificially modify the chemical reactivity of materials at the micro/nano scale using highly focused helium ion beams, thus allowing for localized selective etching by wet-etching agents.…”

A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

“…Local helium ion irradiation has also been shown to modify the chemical properties of a material, for example, chemical etch rates. In HIM studies by Petrov et al irradiating silicon nitride [ 64 – 65 ] and silicon dioxide [ 66 – 67 ] with 10 15 –10 16 ions/cm 2 , the rate of subsequent wet-etching of the irradiated regions with hydrofluoric acid was found to increase by up to a factor of three (for Si 3 N 4 ) and five (for SiO 2 ). The change was attributed to ion-induced defects and demonstrates another potential form of HIM-enabled nanofabrication, namely site-specific ion-enhanced etching with high spatial resolution.…”