Microelectronic Engineering 50 (2000) 171–177 www.elsevier.nl / locate / mee Molecular dynamics characterization of crystalline and amorphous TiSi phases 2 a b a, * Marcella Iannuzzi , Massimo Celino , Leo Miglio a ` Istituto Nazionale di Fisica per la Materia and Dipartimento di Scienza dei Materiali dell’ Universita di Milano-Bicocca, via Cozzi 53, I-20125 Milano, Italy b ENEA–HPCN Project, Centro Ricerche Casaccia, CP 2400-00100 Roma, Italy Abstract Molecular dynamics simulations by a tight binding potential provide new interesting information on the ground state properties of the TiSi phases. In particular, we have compared some structural, elastic, thermodynamic and electronic 2 properties of the C49, the C54 and the amorphous phases. It turns out that the C49 structure is much softer than the C54, also displaying a melting temperature some 300–400 K below the one for the C54, in agreement to very recent experimental results. The amorphous phase is energetically and structurally more akin to the C49 than to the C54 phase. On the basis of these results we suggest the higher formation kinetics of the former to be related to an intrinsic advantage in the growth stage.  2000 Elsevier Science B.V. All rights reserved. Keywords: TiSi ; Amorphous phase; Molecular dynamics; Structural properties; Electronic properties 2 1. Introduction TiSi is widely used in local interconnects of IC, still the fundamental properties of its polymorphic 2 forms are not well established yet. This is particularly true for the metastable C49 phase, which can be grown only as polycrystalline films. Even the exact determination of the unit cell volume (the density) is an open question, since transmission electron microscopy, X-ray diffraction and ab initio 1 calculations do not agree each other. Moreover, the elastic properties of the C49 phase are barely known, and only a few (scattered) parameters are present for the C54 stable structure [2–4]. One interesting thermodynamic information would be the melting temperature of the C49 form, but it is difficult to get it by experiments, since the *Corresponding author. 1 In this paper we used the lattice parameters reported in P. Villars (Ed.), Pearson’s Handbook of Crystallographic Data for Intermetallic Phases [1], Am. Soc. for Metals (1997). Still, the gap in density between the two polymorphic phases is actually very large (8–10%): unpublished XRD measurements by F. d’Heurle and ab initio calculations of ours, as well as reported by Mathias Ekman and Vidvuds Ordins (Phys. Rev. B 57 (1998) 4419), indicate a smaller volume. 0167-9317 / 00 / $ – see front matter  2000 Elsevier Science B.V. All rights reserved. PII: S0167-9317(99)00279-8