K. Fröhlich, R. Luptak, E. Dobrocka, K. Husekova, K. Cico, A. Rosova, M. Lukosius, A. Abrutis, P. Pisecny, J.P. Espinós
Materials Science in Semiconductor Processing, 9 (2006) 1065-1072
doi: 10.1016/j.mssp.2006.10.025

We have prepared rare earth oxides based MOSFET gate stacks using metal-organic chemical vapour deposition, MOCVD. Gd₂O₃, La₂O₃, Nd₂O₃ and Pr₆O₁₁ films with thickness 3–20 nm were deposited on silicon substrate at 500 °C. The films were characterized by X-ray diffraction, X-ray reflectivity, transmission electron microscopy and X-ray photoelectron spectroscopy. As a next step, Ru films were grown on the dielectric films at 300 °C as a gate electrode. Electrical characterization of the MOS structures was performed by capacitance–voltage measurements. The structures annealed at 430 °C in forming gas (90% N₂+10% H₂) exhibited dielectric constant ranging from 12 to 14. Typically, the films showed high values of fixed oxide charge density, . Fixed oxide charges can be decreased by post-deposition annealing in forming gas and in oxygen.