This work reports on the study of two HfO2 metal-insulator-metal structures using two different bottom metal electrodes: Pt and TiN. Different spectroscopic techniques had been used for the physicochemical characterization in order to study the junction interface and determine the oxide thickness and crystallinity: parallel angle resolved x-ray spectroscopy, vacuum ultraviolet ellipsometry, and attenuated total reflectance. Electrical characteristics of the structures with different oxide thicknesses and an evaporated gold counterelectrode are shown. Best results for very thin HfO2 films in terms of voltage linearity are obtained with the platinum electrodes. This is correlated with differences observed between the continuous conductivity when using Pt electrode instead of TiN electrode.