Study of diffusion at surface of multilayered Cu/Au films on monocrystalline silicon C. Benazzouz a, * , N. Benouattas b , S. Iaiche c , A. Bouabellou c a Centre de Recherche Nucl eaire dÕAlger, CRNA, 2 Bd Frantz Fanon, Alger 16000, Algeria b D epartement de Physique, Facult e des Sciences, Universit e Ferhat-Abbas, S etif 19000, Algeria c Laboratoire des Couches Minces et Interfaces, Universit e Mentouri, Constantine 25000, Algeria Abstract Multilayered of pure gold and copper films were evaporated alternatively on (100) monocrystal silicon substrates. Annealing, in a furnace vacuum, were carried out at 200 and 400 °C for 30 min. The obtained samples were analyzed by means of Rutherford backscattering spectrometry, X-ray diffraction and scanning electron microscopy techniques. The interdiffusion of the different elements and the thermodynamic transformations at Cu/Au and Au/Si interfaces have been investigated. Ó 2003 Elsevier B.V. All rights reserved. Keywords: Gold; Silicon; Copper silicides; Morphology; Backscattering spectrometry; Scanning electron microscopy; X-ray diffraction 1. Introduction In the latest generations of logic circuits, one group of materials, the silicides, has proved to be highly beneficial [1]. The silicides form new simple class of materials combining metal with silicon. Specially the near noble metal-rich silicide whose main asset lies in their chemical reactivity. Their utilization depends on the facility to be formed and their stability during the device functioning. Sili- cides are used as ohmic contacts, Schottky barriers and interconnections for microelectronic devices [2]. That is why, actually a big interest is carried to the silicides growth with regard to their utilization in integrated circuits. Indeed, the metal–silicon contact is progressively substituted by the silicide– silicon contact because the silicides offer a better thermal stability and a good adherence on Si and SiO 2 in comparison to simple metals [3]. This work consists to study the interdiffusion and solid state reaction between a thin copper layer and a silicon substrate toward a thin gold layer. Also, in order to prevent the copper diffu- sion and to improve the adherence of films in contact, the effect of the gold film, as diffusion barrier, on the solid state reaction between Cu and Si, is studied. 2. Experimental Prior to loading in the vacuum chamber, Si wafers are degreased in acetone, trichloethylene and methanol baths, and then etched in a diluted * Corresponding author. Fax: +213-21-43-42-80. E-mail address: benazoz@yahoo.fr (C. Benazzouz). 0168-583X/$ - see front matter Ó 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0168-583X(03)01617-3 Nuclear Instruments and Methods in Physics Research B 213 (2004) 519–522 www.elsevier.com/locate/nimb