IBA of ZrO 2 :Yb/Si thin films produced by the spray pyrolysis method E. Andrade a, * , E.B. Ramirez b , J.C. Alonso b , M.F. Rocha c a Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apartado Postal 20-364, 01000 Mexico, Mexico b Instituto de Investigaciones en Materiales, UNAM, Ciudad Universitaria, A.P. 70-360, Mexico D.F. 04510, Mexico c Escuela Superior de Ingenierı ´a Meca ´ nica y Ele ´ctrica, IPN, C.P., Me ´xico D.F. 07738, Mexico Available online 18 March 2008 Abstract A spray pyrolysis method was used to produce thin films of ZrO 2 doped with different Yb concentrations on Si(1 0 0). The films of these ionic semiconductors have potential applications as solid electrolytes in modern ceramic fuel cells of second generation. The deter- mination of the atomic composition of the films is very important because it strongly affects the chemical and thermal stability, as well as electrical properties of the films. A combination of two Ion Beam Analysis (IBA) methods was applied to obtain the atomic composition of the films. A nuclear reaction analysis (NRA) method using a low energy deuterium beam was applied to measure the oxygen content of the films. Heavy ion Rutherford backscattering (HI-RBS) method using a 12 C 3+ beam was applied to measure the Yb and Zr atomic profiles of the samples. X-ray diffraction (XRD) and ellipsometry were also employed to determine structural properties and refractive index of the films, respectively. The IBA, XRD and the ellipsometry supply a wide range of information about the film layers, which can be used for qualification as well as for feedback to the films production. Ó 2008 Published by Elsevier B.V. PACS: 61.10.Eq; 61.10.Ez; 61.66.f Keywords: YbSZ films; Ultrasonic spray pyrolysis; XRD; Ionic conductivity 1. Introduction The preparation of thin films of solid oxide electrolytes by different techniques has become very important for sec- ond-generation solid oxide fuel cells (SOFCs) [1–3]. Due to its high ionic conductivity at high temperatures and chem- ical stability in both oxidizing and reducing atmospheres, yttria stabilized zirconia (YSZ) has been the most widely studied material as solid oxide electrolyte for SOFCs. However, other rare earth elements (Yb, Ce, Gd, etc), has also been investigated as zirconia dopants for such applications [1–3]. A number of studies have shown that the ionic conductivity of stabilized zirconia, which is attrib- uted to the mobility of oxygen vacancies created by the sta- bilizer dopant, is maximum for a certain dopant level (typically 8–20%) and that it tends to be highest as the ionic radius of the dopant closely matches that of Zr +4 host cat- ion [3,4]. Tablets and/or bars prepared from compactation and sintering of fine grained powders of stabilized zirconia with ytterbia (YbSZ) have been reported to have a conduc- tivity higher than that of YSZ [2,5]. However, to our knowledge, there are scarce reports on the preparation, composition and structure of YbSZ thin films [6]. In this work, we report the preparation of YbSZ thin films with different content of Yb, by the spray pyrolysis method. The atomic composition of the YbSZ films was measured using IBA methods. There are different IBA methods able to provide the film stoichiometry of the Yb and Zr oxides. We selected a combination of two IBA methods as the most favorable: (a) a RBS/NRA method using a low energy deuterium beam was applied to obtain the oxygen concentration through nuclear reactions (NR) produced on oxygen nuclei. This method lacks good mass separation and has a poor depth resolution; (b) a HI- RBS method using a 12 C 3+ was applied to measure the 0168-583X/$ - see front matter Ó 2008 Published by Elsevier B.V. doi:10.1016/j.nimb.2008.03.080 * Corresponding author. Tel.: +52 55 5622 5055; fax: +52 55 5622 5046. E-mail address: andrade@fisica.unam.mx (E. Andrade). www.elsevier.com/locate/nimb Available online at www.sciencedirect.com Nuclear Instruments and Methods in Physics Research B 266 (2008) 2433–2436 NIM B Beam Interactions with Materials & Atoms