Ž . Thin Solid Films 317 1998 241–244 Yttria-stabilized zirconia obtained by MOCVD: applications G. Garcia a, ) , A. Figueras a , J. Casado b , J. Llibre b , M. Mokchah c , G. Petot-Ervas c , J. Calderer d a ICMAB r CSIC, Campus UAB, Bellaterra, 08193, Spain b S.E. Carburos Metalicos, Po. Zona Franca, 14-20, Barcelona, 08038, Spain ´ c CNRS-URA 453, Laboratoire de Chimie-Physique du solide, Ecole Centrale de Paris, Chatenay-Malabry, Cedex, 92295, France d Departament d’Enginyeria Electronica Modul C4-UPC, c r Gran Capita s r n, Barcelona, 08034, Spain ` ` ` Abstract Ž . Ž . This paper deals with the preparation and characterization of YSZ layers obtained by MOCVD using Y thd and Zr thd , where 3 4 Ž . thd s2,2,6,6,-tetramethyl-3,5-heptanedionate, as organometallic precursors. Yttria-stabilized zirconia YSZ layers deposited on porous alumina covered with LaSrMnO electrodes were used as solid electrolytes. Electrical characterizations were carried out by Spectral 3 Complex Impedance measurements on multilayer devices such as airrelectroderYSZ electrolyterelectroderAl O porousrair, showing 2 3 very promising results. q 1998 Elsevier Science S.A. Keywords: YS2; Electrodes; MOCVD 1. Introduction For many years, zirconia has attracted the attention of scientists and technologists because of its combined me- chanical, chemical and electrical properties. It is well Ž known that zirconia has many polimorphic phases mono- . clinic, tetragonal and cubic phase and that its toughening Ž . transformation tetragonal to monoclinic has resulted in wx improved mechanical properties in ceramics 1 . Also, the high melting point temperature and chemical inertness of Ž . cubic yttria-stabilized zirconia YSZ are the basis for its extensive use as a refractory material and as buffer layer for the deposition of high Tc superconducting films on w x technological substrates 2–4 such as silicon and sapphire. The stabilization of the cubic structure by addition of dopant oxides such as yttrium oxide produces oxygen vacancies which are believed to be the main defect in- wx volved in the ionic conductivity of this material 5 . The major applications of this high ionic conductivity include wx wx oxygen sensors 6 , electrochemical oxygen pumps 7 and wx high temperature fuel cells 8 . In contrast to the large number of reports dealing with YSZ buffer layers de- posited by MOCVD, there is a lack of literature concern- ing the preparation of YSZ by MOCVD for solid elec- trolyte applications. ) Corresponding author. This paper deals with the obtention and characterization of YSZ thin films deposited by MOCVD for solid elec- trolyte applications in oxygen pumps. Lantanum strontium Ž . manganite La Sr MnO or LSM electrodes de- 0.85 0.15 3 posited by sputtering on porous alumina were used as substrates. This electrode material has a high electrical conductivity, presents a thermal expansion coefficient sim- ilar to the YSZ one and is chemical compatible with the wx Ž . YSZ 9 . The perovskite LSM was prepared on porous alumina to allow the exchange reactions with the gaseous phase. 2. Experimental Ž . This perovskite-type oxide LSM was obtained by sputtering in a Leybold Z400 diode configuration equip- ment. A powered LSM target was used as cathode and the material was sputtered onto a tablet of porous alumina, heated at 2008C, in an argon pressure of 4.10 y2 mbar. The Ž . RF potential was 600 V RFr13.56 MHz . Film thickness was approximately 900 nm. The deposition rate was around 0.1 m mrh. The as-sputtered films were annealed at 8008C for 5 h to allow recrystallization of the deposited material. The X-ray diffraction patterns of the annealed LSM films showed only the reflections due to the corresponding perovskite structure. LSM was used as a substrate for the deposition of the electrolyte film by MOCVD. 0040-6090r98r$19.00 q 1998 Elsevier Science S.A. All rights reserved.