Ion beam mixing and room temperature silicidation of Cu/Si(1 1 1) system by Ar  ion irradiation D.K. Sarkar a, * , S. Dhara b , K.G.M. Nair b , S. Chaudhury c a Institute of Physics, Chemnitz University of Technology, D-09107 Chemnitz, Germany b Materials Science Divisions, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India c Department of Physics, University of Kalyani, Kalyani 741 235, West Bengal, India Abstract Ion beam mixing has been extensively used in Metal/Metal and Metal/Silicon systems to produce the new phases. In the present study a Cu ®lm of thickness 500  A was deposited by thermal evaporation at a pressure of 8  10 4 Pa on 5% HF etched Si(1 1 1). The ®lms were irradiated with 80 keV Ar  ions at room temperature with dierent doses. The Rutherford Backscattering Spectrometry (RBS) were carried out to determine the extent of mixing. The experimentally observed mixing width is compared with AndersonÕs cascade mixing model and the experimentally observed data are found to be very well consistent with the model. The Grazing Incidence X-Ray Diraction (GIXRD) was carried out to determine the crystalline phase formation of the ion beam mixed Cu/Si(1 1 1) system. The presence of the new peaks apart from Cu(1 1 1) and Cu(2 0 0) con®rms the crystalline phase formation. The observed diraction lines have been indexed with the Cu 0:83 Si 0:17 phase which is dierent from the thermally grown Cu 3 Si phase. Ó 2000 Elsevier Science B.V. All rights reserved. PACS: 68.10.Eq; 68.55.Ln; 68.10.Nq Keywords: Ion beam mixing; Copper silicide; GIXRD 1. Introduction Materials under ion irradiation undergo sig- ni®cant atomic rearrangement. The most obvious example of this phenomenon is the atomic inter- mixing and alloying that can occur at the interface separating two dierent materials during ion irra- diation. This process is known as the ion beam mixing [1,2]. The various processes which give rise to ion beam mixing are ballistic mixing, recoil mixing and cascade mixing. Among these mixing process, cascade mixing is a more realistic process for the metal silicon systems. The detailed theo- retical formulation of the cascade mixing has been described by Sigmund and Gras-Marti [3], based on linear transport theory. Ion beam induced mixing of Cu/Si system has been studied by Abu El-Hija et al. [4] using Rutherford Backscattering Nuclear Instruments and Methods in Physics Research B 161±163 (2000) 992±996 www.elsevier.nl/locate/nimb * Corresponding author. Tel.: +49-371-531-3092/3102; fax: +49-371-531-3077. E-mail address: dilip.sarkar@physik.tu-chemnitz.de (D.K. Sarkar). 0168-583X/00/$ - see front matter Ó 2000 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 5 8 3 X ( 9 9 ) 0 0 7 7 4 - 0