Characterisation of HfO2 deposited by photo-induced chemical vapour deposition

Abstract The deposition of thin Hafnia (HfO 2 ) films on crystalline Si by photo-induced chemical vapour deposition (CVD) using 222 nm excimer lamps at temperatures between 300 and 450 °C is presented. Hafnium (IV) tetra- t -butoxide was used as the precursor, which was carried into the photochemical reaction chamber by flowing Ar carrier gas at a pressure of several mbar using a special precursor injection system. Films from approximately 6–70 nm in thickness with refractive indices from 1.60 to 1.85 were grown. The deposition rate measured by ellipsometry was found to be 15 nm min −1 at a temperature of 400 °C. The deposited HfO 2 films were characterised by various techniques. XRD showed that as-deposited HfO 2 films were basically amorphous. Fourier transform infrared spectroscopy, revealed that Hf-O absorption in the photo-CVD deposited HfO 2 films is quite different at various deposition parameters. The substrate temperature, system pressure and UV-annealing dependence of the physical and interfacial properties of these films will also be presented.