SEM and XPS studies of titanium dioxide thin films grown by MOCVD

Abstract

The metal organic chemical vapour deposition (MOCVD) method was used to prepare titanium dioxide thin films. Thin films of TiO 2, about 100 nm thick, were deposited on (100)Si and (11̄02)Al 2O 3 sapphire substrates using titanium isopropoxide (Ti(OC 3H 7) 4) as metal organic precursor. The morphology of the films and the presence of impurities on the thin films surfaces were studied using respectively, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The influence of the growth parameters such as the deposition temperature, the carrier gas (nitrogen) flow rate and the presence of an additional oxygen flow on the characteristics of the titanium dioxide films has been studied. The morphology of the deposits has been shown to be greatly influenced by the growth parameters (temperature, substrate and carrier gas flow rate). The main impurity of the layer, carbon, has been found by XPS to be a function of both the growth temperature and the nature of the substrate. Moreover, it has been evidenced that an additional oxygen flow is not essential to obtain stoichiometric titanium dioxide films.