Cubic phase stabilization and improved dielectric properties of atomic-layer-deposited EryHf1-yOx thin films

The electrical and physical properties of atomic-layer-deposited Er y Hf 1-y O x thin films have been investigated with different stoichiometries of erbium oxide (Er 2 O 3 ) and hafnium oxide (HfO 2 ). The as-deposited and annealed Er y Hf 1-y O x films exhibit much higher dielectric constants than the reported k -values of the corresponding binary oxides. The highest k -value of 37.6 ± 1 is achieved with 13 at.% of erbium in the film. The enhancement in dielectric constant is due to the formation of the cubic HfO 2 phase stabilized by erbium, as revealed by x-ray diffraction experiments. The annealed mixed oxide films exhibit remarkably low oxide charges, low interface states, low leakage, and good breakdown electric fields.