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Al Doped Ta2O5 Thin Films for Microelectronic Applications P. C. Joshi, M. W. Cole, C. W. Hubbard, and E. Ngo US Army Research Laboratory, Weapons and Materials Research Directorate, Aberdeen Proving Ground, MD 21005, U.S.A. ABSTRACT In this paper, we report on the fabrication and characterization of pure and Al doped Ta2O5 thin films fabricated by metalorganic solution deposition (MOSD) technique. The pure and Al doped Ta2O5 thin films were fabricated by spin-coating technique using room temperature processed carboxylate-alkoxide precursor solution. The structure of the films was analyzed by xray diffraction (XRD). The surface and cross-sectional morphology of the films were examined by field emission scanning electron microscope (FESEM) and atomic force microscope (AFM). The electrical measurements were conducted on films in MIM configuration using Pt as the top and bottom electrode. The effects of Al concentration and the post-deposition annealing temperature on the structural, dielectric, and insulating properties were analyzed. The effects of the applied bias and the measurement temperature on the dielectric and insulating properties were also analyzed to establish the stability and reliability of Al doped Ta2O5 thin films. INTRODUCTION Tantalum oxide, Ta2O5, thin films have been extensively investigated for various electronic applications, including gate dielectric of MIS devices, decoupling capacitors, optical waveguides, electroluminescent display devices, and surface acoustic wave devices [1-5]. Ta2O5 is one of the most promising insulator materials for DRAM cell capacitors because of its high dielectric constant, low dielectric loss, low leakage current, low defect density, and good temperature and bias stability. The high dielectric constant and low dielectric loss materials are also attractive for integrated microwave applications [4]. For successful integration into microelectronic devices, extremely reliable Ta2O5 thin films are desired. Bulk Ta2O5 based composites have been investigated to improve the dielectric and insulating properties of tantalum oxide [6]. It was shown that the dielectric properties of bulk Ta2O5 could be significantly improved through 10% substitution with Al2O3. The (1-x)Ta2O5-xAl2O3 material is attractive as it is expected to be compatible with semiconductor processing where both Ta and Al are already in use. In this paper, we report on the fabrication of pure and Al doped Ta2O5 thin films by metalorganic solution deposition (MOSD) technique. The MOSD technique has the potential to control chemical composition, stoichiometry, purity, and homogeneity, which are critical features for the fabrication of high quality electronic components. The effects of Al content on the structural, dielectric, and insulating properties of the thin films have been investigated. The effects of the post-deposition annealing temperature, measurement temperature, and the applied bias on the microstructure and electrical properties have also been analyzed. EXPERIMENTAL The (1-x)Ta2O5-xAl2O3 thin films