Ion-, photoelectron- and laser-assisted analytical investigation of nano-structured mixed HfO_2-SiO_2 and ZrO_2-SiO_2 thin films

摘要

In this study, the surface and depthwise composition of hafnium- and zirconium-based inorganic-organic hybrid layers, as well as of binary HfO_2-SiO_2 and ZrO_2-SiO_2 thin films, obtained by calcination at high temperature (T = 800℃) of the hybrid films, were analysed by using different analytical methods which can deliver complementary information on chemical composition and both in-depth and lateral distribution of the species. In particular, X-ray photoelectron spectroscopy (XPS) was used to investigate the chemical composition of the thin films (quantitative analysis, oxidation states, nature of the interaction between host matrix and guest species) on the surface as well along the film thickness. The depthwise distribution of the involved species was thoroughly investigated by means of secondary ion mass spectrometry (SIMS). Information concerning the lateral distribution of the species was gained also by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Finally, the dielectric response of two samples was characterized through broadband dielectric spectroscopy, which provided a value of ε′(ω) ranging from 7.5 to 9.5 for a film without the cluster, while in a sample embedding the hafnium cluster these values range in the interval 7.2-7.4. The information obtained by the different analytical methods demonstrated the formation of a homogeneous in-depth nanocomposition of the thin films, which would be suitable for frontier applications.