Surface and Coatings Technology 158–159 (2002) 214–218 0257-8972/02/$ - see front matter  2002 Elsevier Science B.V. All rights reserved. PII:S0257-8972 Ž 02 . 00210-4 Electronic-loss induced ion beam mixing in various materials studied using SIMS technique S.K. Sinha , D.C. Kothari *, A.K. Balmuragan , A.K. Tyagi , D. Kanjilal a a, b b c Department of Physics, University of Mumbai, Vidyanagari, Mumbai 400098, India a Material Science Division, IGCAR, Kalpakkam 603 102, India b Nuclear Science Centre, P.O. Box No. 10502, New Delhi 110067, India c Abstract Ion beam mixing of multilayer thin films using MeV ion irradiation is described in this paper. Iodine ion beam irradiation at 90 and 100 MeV on FeySi, TiySi, FeyTi, ZrySi and ZryTi multilayer thin films are carried out such that electronic losses predominate and the ions do not get implanted in the films. Ion irradiation fluences range from 1=10 ionsycm to 1=10 13 2 14 ionsycm . Depth profiles of the films at various interfaces are measured using SIMS technique. The interface profile in each case 2 is fitted with a complementary error function to determine the diffusion lengths of species A in species B or vice versa in multilayer AyB films. Mixing is observed at FeySi, TiySi and ZrySi interfaces and no mixing at FeyTi and TiyZr. The mixing rate in SiyTifilmsishigherataniondoseof5=10 ionsycm than at 2.5=10 ionsycm.InanFeySisystem,completemixing 13 2 13 2 is observed. It is concluded that the amorphous nature of Si is responsible for inducing mixing in the present experiments.  2002 Elsevier Science B.V. All rights reserved. PACS: 66.30J; 66.30N; 68.22; 68.55 Keywords: SIMS; Electronic-loss; Ion beam mixing 1. Introduction Ion beam mixing using keV beams is now a well- understood subject w1x. In this energy regime, mixing of two species A and B at the interface of multilayer AyB films is mainly caused by ballistic effects, so-called ‘nuclear-loss’ induced ion beam mixing. At higher ener- gies, ions lose energy predominantly to the electronic system of the material, which is called ‘electronic-loss’. Although electronic-loss is not expected to cause dis- placement of the lattice atoms in metals, recent years have seen many effects involving atomic displacement suchasdamagecreation w2x,anisotropicgrowthinmetal glasses w3,4x, annealing w5x, phase transformation w6x, amorphization w7x and ion beam mixing w8x. Using Mossbauer spectra, an Fe ySi multilayer film ¨ has been shown to be completely mixed after 650 MeV uranium ion irradiation to a fluence of 10 ions ycm 13 2 *Corresponding author. Tel.: q91-22-652-6709; fax: q91-22-652- 6250. E-mail address: dkothari@vsnl.com (D.C. Kothari). w8x. The above results indicate that the target atoms experience several tens of jumps in the ion wake. In caseofmixingofanFe yZr multilayered film w9x,astep dependence on ion fluence was observed. Two-stage mixing was observed, first the inter-diffusion at the interfaceandsecondthecompletemixing.Theinfluence of the amorphous state of Zr was indicated to be a possible cause of mixing w9x. Another study on mixing of Fe ySi multilayer films suggests that mixed phases and mixing kinetics are different at higher electronic losses from those in the lower electronic loss regime w10x. It has been shown that the intermixing kinetics is similar to that in thermal diffusion processes in the case of Fe ySi systems w10x. Mixing mechanisms in Fe ySi multilayer films are shown to be the same whether Fe is in crystalline form or amorphous, where Si is amor- phous in both cases w11x. It has been shown using ERDA that several tens of atoms are displaced at the interface of Fe ySi, CuOyglass bilayer films by a 210 MeV single iodine ion w12x. The above-mentioned literature indicates that elec- tronic-loss induced ion beam mixing is possible. How-