Materials Chemistry and Physics 125 (2011) 757–762 Contents lists available at ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys CVD of Ru, Pt and Pt-based alloy thin films using ethanol as mild reducing agent P. Antony Premkumar a,1 , N.S. Prakash b , F. Gaillard b , N. Bahlawane a,∗ a Physikalische Chemie I, Fakultät für Chemie, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany b Institut de recherches sur la catalyse et l’environnement de Lyon (IRCELYON), UMR 5256 CNRS - Université de Lyon, 2 avenue Albert Einstein, 69626 Villeurbanne cedex, France article info Article history: Received 25 April 2010 Received in revised form 29 June 2010 Accepted 22 September 2010 Keywords: Noble metals Pulsed spray CVD (PSE-CVD) Alcohols Incubation time abstract Noble metal thin films (Pt and Ru) were grown at 250 ◦ C, using commercially available precursors, by the pulsed spray evaporation chemical vapor deposition (PSE-CVD) technique. The growth process relies on the thermally activated reaction of ethanol with the metal acetylacetonate precursors. The synthesized polycrystalline films are pure metal phase and crystallize in hexagonal (Ru) and cubic (Pt) structures. The formation of an interfacial silicide phase was noticed in the case of the Pt growth on silicon substrates. The films are smooth, continuous and show a steady growth without any noticeable incubation time. The single-step growth of Pt-based alloys, Pt–Co and Pt–Cu, with controlled composition was performed by simply adjusting the composition of the liquid feedstock. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Noble metals especially Pt and Ru, are required for many appli- cations such as electrodes for dynamic and ferroelectric random access memories (DRAM and FRAM’s), ohmic and Schottky diode contacts, integrated circuits, diffusion barriers, corrosion resistant films, coatings for high temperature crucibles and the prepara- tion of solid supported catalysts owing to their good electrical conductivity, excellent chemical robustness, high thermal stability and melting points [1–6]. Recently, Pt-3d transition metal alloys have attracted a wide attention due to their potential technolog- ical applications. Due to its strong magnetocrystalline anisotropy and high coercivity, the ordered phase of CoPt alloys (L1 0 structure) and of the Co-rich Co–Pt (Pt ∼ 20 at.%) find particular applications as magnetic patterned media for advanced recording devices and magnetic actuators for microelectromechanical systems [7]. When alloyed with Co and Cu, Pt was found to exhibit improved catalytic activity for the oxygen reduction reaction (ORR) in polymer elec- trolyte [8] or proton exchange membrane fuel cells [9] as well as in the heterogeneous reactions for the production of basic chemicals [10] and NO x reduction [11]. Among the various techniques available for thin film fabri- cation, CVD offers numerous advantages such as low processing temperatures, excellent conformality and step coverage in com- plex features, selective growth, radiation-damage-free deposition ∗ Corresponding author. Tel.: +49 0521 106 2199; fax: +49 0521 106 6027. E-mail address: naoufal@pc1.uni-bielefeld.de (N. Bahlawane). 1 Current address: Plasma and Materials Processing Group, Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, MB 5600, The Nether- lands. combined with high throughput and growth rates, mandatory for commercial production. Although the CVD of noble metals is well documented in the literature [1,3,12–17], the development and success of the process are restricted, primarily due to the lack of suitable precursors, which need to be highly volatile, thermally stable, non-toxic and inexpensive. In the past, CVD of noble metals was widely performed using either the metallo-organic (MO) or organo-metallic (OM) family of precursors. Source reagents from MO mainly comprise -diketonates (also known as acetylaceto- nates) and their structural analogues, while the OM complexes (which have direct metal–carbon bonds) feature derivatives of car- bonyl, isonitrile, alkyl, allyl, cyclopentadienyl or octadienyl organic moieties. Although most of the OM source reagents are liquids and volatile, they are not commercially or readily available [14]. It is inconvenient to handle some of them due to their sensitivity towards air, light, moisture and temperature [14,18]. Furthermore, their preparation involves tedious synthetic procedures yet only resulting in low yields [12]. It has been shown that reactive carrier gases such as H 2 or O 2 are essential to grow carbon-free noble metal films and to reduce the deposition temperature, irrespective of the precursor family used [1,2,13,16]. Nevertheless, H 2 and O 2 can also result in the reductive or oxidative dissociation of the precursors in the gas phase which deteriorates the quality of the films [1,12,19]. Furthermore, the use of H 2 is prohibited in certain applications as it degrades the electrical properties of the platinum films [1]. For the application of Pt as bottom electrodes for multicomponent oxides (MCOs) like Ba x Sr 1-x TiO 3 (BST), PbZrTi 1-x O 3 (PZT) and SrBi 2 Ta 2 O 9 (SBT), the use of H 2 is not desirable since the atomic hydrogen generated by the catalytic activity of Pt particles could deteriorate the dielectric properties of the MCO [3]. Likewise, oxygen might incorporate into the Pt and Ru films and can eventually diffuse and oxidize the adhesion layer 0254-0584/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.matchemphys.2010.09.062