Materials Chemistry and Physics 132 (2012) 421–430 Contents lists available at SciVerse ScienceDirect Materials Chemistry and Physics j ourna l ho me pag e: www.elsevier.com/locate/matchemphys Temperature and thickness dependence of the grain boundary scattering in the Ni–Si silicide films formed on silicon substrate at 500 ◦ C by RTA G. Utlu ∗ , N. Artunc ¸ , S. Selvi Ege University, Faculty of Science, Department of Physics, 35100 Bornova, Izmir, Turkey a r t i c l e i n f o Article history: Received 6 December 2010 Received in revised form 5 November 2011 Accepted 21 November 2011 Keywords: Thin films Evaporation Annealing Electrical properties a b s t r a c t The temperature-dependent resistivity measurements of Ni–Si silicide films with 18–290 nm thicknesses are studied as a function of temperature and film thickness over the temperature range of 100–900 K. The most striking behavior is that the variation of the resistivity of the films with temperature exhibits an unusual behavior. The total resistivity of the Ni–Si silicide films in this work increases linearly with tem- perature up to a T m temperature, thereafter decreases rapidly and finally reaches zero. Our analyses have shown that in the temperature range of 100 to T m (K), parallel-resistor formula reduces to Matthiessen’s rule and  D Debye temperature becomes independent of the temperature for the given thickness range, whereas at high temperatures (above T m ) it increases slightly with thickness.  D Debye temperature have been found to be about 400–430 K for the films. We have also shown that for temperature range of 100 to T m (K), linear variation of the resistiv- ity of the silicide films with temperature has been caused from both grain-boundary scattering and electron–phonon scattering. That is why, resistivity data could have been analyzed in terms of the Mayadas–Schatzkes (M–S) model successfully. Theoretical and experimental values of reflection coef- ficients have been calculated by analyzing resistivity data using M–S model. According to our analysis, R increases with decreasing film thickness for a given temperature, while it is almost constant for the thickness range of 200–67 nm and 47–18 nm, over which silicide films show almost the same phases, also confirmed by our XRD, SEM and RBS measurements. © 2011 Elsevier B.V. All rights reserved. 1. Introduction In recent years silicides, intermetallic compounds of silicon and transition metals have received much attention because of their wide application in very large-scale integrated circuits (VLSI) and ultra large-scale integrated circuits (ULSI) [1–3]. These structures show metallic behavior with low electrical resistivity, high electro- migration resistance, high thermal stability and some resistance to acids [1,4]. Due to these properties, they have been proposed as probable candidates for replacing aluminum alloys for applications in microelectronics [3–5]. It is the well known fact that the resistivity of thin metallic films (or metallic nanostructures) is greater than that of the bulk material and this resistivity of the former increases with decreasing film thickness. It has been pointed out in earlier studies that, the total resistivity of a film can be given by  f (T) =  ∞ (T) + , where  f (T) and  ∞ (T) is the measured total resistivity of the film and the bulk sample, respectively [6–8].  term is the resistivity known as the size-effect dependent deviation of the Mathiessen’s rule (MR). ∗ Corresponding author. Tel.: +90 232 3112361; fax: +90 232 3881036. E-mail address: gokhan.utlu@ege.edu.tr (G. Utlu). Both Fuch–Sondheimer (F–S) theory [9,10] and Mayadas Shatzkes (M–S) model [11] lead to resistivity increase, . Accord- ing to the F–S theory, electrons scatter at the surface of the thin film only. On the other hand, M–S model involves electrons scat- tering not only at the surface but also at the grain-boundaries of the film. Therefore, temperature-dependent resistivity measure- ments are necessary for distinguish between the grain boundary scattering and the surface scattering. For this reason, the temper- ature dependent resistivity measurements of Ni–Si silicide films have been studied as a function of temperature and film thickness in a wide temperature range of 100–900 K. In most silicides, thermal contribution to the total resistivity increases linearly with temperature such as in metals. But in some silicides (TaSi 2 , WSi 2 , etc.) resistivity deviates from linearity at high temperatures. The resistance arises from electron scattering when the deviation from periodicity in a lattice increases. We know that most important electron scatterers are phonons and impurities in metals and at low temperature, electron impurity component  0 dominates the total resistivity (T), whereas the electron–phonon component  e–p (T) dominates at high temperatures. It has been pointed out in previous studies that, parallel–resistor formula is used for analyzing the temperature dependent resistivity data for several thin films and metal silicide films in a wide temperature 0254-0584/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.matchemphys.2011.11.048