Study on mechanism of crystallization in HfO2 films on Si substrates by in-depth profile analysis using photoemission spectroscopy

We have investigated the effect of HfO2 layer thickness on crystallization in thin HfO2 films using photoemission spectroscopy and x-ray absorption spectroscopy (XAS). O K-edge XAS spectra depending on annealing temperature indicate that crystallization in thin HfO2 films is suppressed upon annealing for thin HfO2 film, which in turn has a beneficial effect on the performance of devices. The annealing-temperature dependence of the depth profile of HfO2 films suggests that diffusion of Si atoms into the HfO2 layer plays only a minor role in the suppression of crystallization, indicating that HfO2 films can restrain a decrease in dielectric constant.