On the mechanism of ion-induced bending of nanostructures

• Published in: Applied surface science 2018-07, Vol.446, p.151-159
• Main Authors: Gomes, Diego R., Turkin, Anatoliy A., Vainchtein, David I., De Hosson, Jeff Th.M.
• Format: Article
• Language: English
• Subjects: Focused ion beam; Nanostructure fabrication; Radiation-induced bending
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2018.02.015

[Display omitted] •A new model for ion-induced bending of free-standing metallic thin films is proposed.•The mechanism relies on accumulation of interstitial loops beyond the implanted range.•The technique has great potential in fabrication of nano- and micro-sized devices. This contribution concentrates on ion-induced bending phenomena which may serve as a versatile tool to manufacture nanostructured devices. In particular bending was studied in free standing Au cantilevers. The preparation and irradiation of the cantilevers were performed using a TESCAN LYRA dual beam system. Cantilevers with thicknesses ranging between 90 and 200 nm were irradiated with 30 keV Ga ions normal to the sample surface up to a maximum fluence of ∼3 × 1020 Ga/m2. The bending of the cantilevers towards the incident beam is discussed in terms of local volume change due to accumulation of radiation-induced vacancies and substitutional Ga atoms in the Ga implantation layer, as well as due to accumulation of interstitial type clusters in the region beyond the Ga penetration range. A model is proposed to explain the observations, based on a set of rate equations for concentrations of point defects, i.e. vacancies, self-interstitials and implanted Ga atoms. The influence of preexisting defects is also discussed. The work shows that an in-depth understanding the ion-beam bending can play a predictive role in a quantitative control in for the micro- and nanofabrication of small-sized products.