Characterization of Gd[sub 2]O[sub 3] Films Deposited on Si(100) by Electron-Beam Evaporation

Gadolinium oxide films were deposited on Si(100) substrates from a rod-fed electron beam evaporator using a pressed-powder target. Films 25 nm thick were shown to be stoichiometric by Rutherford backscattering and had a dielectric constant at 100 kHz of 16.0 ± 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 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 layer. The characteristics of the leakage currents through the gadolinium oxide were consistent with a Frenkel-Poole conduction mechanism with a silicon- band offset of 1.8 V. Interfaces with excellent electrical properties, characteristic of good were obtained after annealing in oxygen. Annealing of the films in vacuum prior to oxygen annealing reduced the thickness of the interfacial silicon dioxide. © 2001 The Electrochemical Society. All rights reserved.