Gadolinium oxide films were deposited on Si͑100͒ substrates from a rod-fed electron beam evaporator using a pressed-powder Gd 2 O 3 target. Films 25 nm thick were shown to be stoichiometric Gd 2 O 3 by Rutherford backscattering and had a dielectric constant at 100 kHz of 16.0 Ϯ 0.3. Transmission electron microscopy and X-ray reflectivity measurements showed that films 7-13 nm thick annealed in oxygen consisted of three distinct layers, an interfacial silicon dioxide layer next to the substrate, a second amorphous oxide layer containing silicon, gadolinium, and oxygen above this, and a polycrystalline Gd 2 O 3 layer on top. Annealing in oxygen reduced the leakage currents, increased the thickness of the silicon dioxide layer, and increased the grain size of the top Gd 2 O 3 layer. The characteristics of the leakage currents through the gadolinium oxide were consistent with a Frenkel-Poole conduction mechanism with a silicon-Gd 2 O 3 band offset of 1.8 V. Interfaces with excellent electrical properties, characteristic of good SiO 2 , were obtained after annealing in oxygen. Annealing of the films in vacuum prior to oxygen annealing reduced the thickness of the interfacial silicon dioxide.

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