Gadolinium oxide thin films have been deposited on Si(I 0 0) by atomic layer deposition (ALD) using as precursors either a beta-diketonate-type chelate, namely Gd(thd)(3) (thd = 2,2,6,6-tetramethyl-3,5-heptanedione) and ozone or a true organometallic (CpCH3)(3)Gd (Cp = cyclopentadienyl, -C5H5) together with water. Self-limiting ALD growth mode was detected for the Gd(thd)(3)/O-3 process at 300 degrees C with a growth rate of 0.3 angstrom/cycle. In the case of the (CpCH3)(3)Gd/ H2O process, partial decomposition of the metal precursor affected the film growth mechanism. However, at 250 degrees C, the uniform films obtained from (CpCH3)(3)Gd and H2O showed almost an ideal stoichiometry with low impurity contents (e.g. 0.5 at% of C) as analyzed by time-of-flight elastic recoil detection analysis (TOF-ERDA). X-ray diffraction data indicated that Gd2O3 films obtained by the Cp-based process were crystalline with cubic C-type structure when deposited even at 150 degrees C. The strongest reflection changed from (4 0 0) to (2 2 2) at deposition temperatures around 200 degrees C. Oxygen-rich films grown by the Gd(thd)3/03 process were amorphous at deposition temperatures below 250 'C but crystalline with (400) dominant reflection at temperatures exceeding 250 degrees C. The films were smooth with both processes at the optimized deposition temperatures. In addition, the dielectric properties were analyzed showing effective permittivity of about 13 for the (CpCH3)(3)Gd/H2O-processed Gd2O3 films. (c) 2005 Elsevier B.V. All rights reserved.