La-based ternary rare-earth oxides as alternative high-k dielectrics

Amorphous LaScO3 and LaLuO3 thin films have been grown by molecular-beam and pulsed-laser deposition on Si substrates, respectively. The depositions were performed at room temperature, 250 or 450 degrees C. Electrical characterization of the films reveal C-V curves with a small hysteresis and low leakage current densities. LaScO3 and LaLuO3 films prepared at room temperature show a dielectric constant of similar to 17. Much higher kappa values of around 30 could be achieved when the films were deposited on heated substrates. We correlate this improvement to the achievement of an oxygen stoichiometry close to the nominal stoichiometric composition