5 nm thick lanthanum oxide thin films grown on Si(100) by atomic layer deposition: The effect of post-annealing on the electrical properties

Amorphous stoichiometric lanthanum oxide (La₂O₃) thin films were grown on Si(100) by atomic layer deposition technique using lanthanum 2,2,6,6-tetramethyl-3,5-heptanedione and water (H₂O) as precursors. The structural and electrical properties were investigated by transmission electron microscope, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), current-voltage (I-V) and capacitance-voltage (C-V) measurements. In particular, the effects of thermal annealing on the La₂O₃ film properties such as crystallinity, I-V, and C-V characteristics were measured. Post-annealing at 700 °C improved the electrical properties to reduce the leakage current density up to 2 × 10^{- 7} A/cm² at the bias voltage of + 1 V. It was also observed that the capacitance increased and the shift of the flat band voltage, V_FB, disappeared with the post-annealing.