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HfLaO and HfO2 films were deposited by plasma enhanced atomic layer deposition (PEALD). PEALD makes in-situ plasma treatment possible, and the film growth temperature can be reduced. The films were characterized. High resolution transmission electron microscopy (HRTEM) indicated both films were amorphous. X-ray photoelectron spectroscopy (XPS) suggested that the interface layer was most likely composed of Hf-Si-O and La-Si-O. MIS capacitors with HfLaO and HfO2 dielectrics were irradiated by gamma rays with the dose up to 2×106 rad (Si). Electrical measurements indicated that the dielectrics showed relatively stable electrical properties. The equivalent oxide thicknesses (EOT) of HfLaO samples were calculated to be 0.9 nm. At a gate condition of |Vg-Vfb| = 1 V, the leakage current densities were 0.02 mA/cm2. With the increasing of the radiation dose, the maximum oxide trap charge density and interface trap charge density for HfLaO samples were calculated to be 2.6×106 cm-2 and 1.2×1012 cm-2, respectively. The analysis of the IV curves suggested that the conduction mechanism in HfLaO samples is the Poole-Frenkel emission.