Characterization of lanthanum lutetium oxide thin films grown by atomic layer deposition as an alternative gate dielectric

LaLuO3 thin films have been deposited with atomic layer deposition on Si substrates using β-diketonate compounds for the rare earth metals and ozone as the oxygen source. Subsequently, the films were investigated regarding their chemical composition, morphology, and electrical characteristics. The as deposited films are amorphous, uniform, and smooth but reveal an excess of oxygen and a low κ-value of ∼17. Oxygen annealing of the films at 800 °C for 5 min leads to a reduction of the oxygen content and a dramatic increase of the permittivity to ∼30 but also to a crystallization of thick films.