Phase transformations in hafnium dioxide thin ®lms grown by atomic layer deposition at high temperatures

High-temperature cubic phase of HfO2 was observed by re¯ection high-energy electron diffraction in nanocrystalline thin ®lms grown by atomic layer deposition from HfCl4 and H2O at substrate temperatures of 880±9408C. The phase was formed at properly chosen precursor doses and it was observed on the surface of ®lms, which according to X-ray diffraction data consisted of monoclinic HfO2. The thickness of the surface layer, in which the cubic phase appeared, was estimated to be 5±10 nm. According to Auger electron spectroscopy data, formation of the cubic phase was accompanied with an increase in the ionicity of O±Hf bonds. # 2001 Elsevier Science B.V. All rights reserved.