Growth of TiO₂ with Thermal and Plasma Enhanced Atomic Layer Deposition

We show a comparative study of the TiO₂ ALD with TTIP and either O₂ or O₂-plasma on Si/SiO₂ substrates. In particular we compare the surface morphology and crystalline phase by means of Atomic Force Microscopy (AFM), X-ray Photoelectron Spectroscopy (XPS) and X-ray Absorption Spectroscopy (XAS) for different O₂-plasma procedures upon changing the time between cycles and the N₂-purging pressure. The AFM images show that already these parameters may induce structural changes in the TiO₂ films grown by ALD, with the formation of crystallites with average lateral width varying between 15 and 80 nm. By means of XAS we also found that the crystallites have mixed anatase and rutile crystalline phases and that smaller crystallites have a greater rutile component than the larger ones.