Step coverage of thin titania films on patterned silicon substrate by pulsed-pressure MOCVD

Thin titania (TiO2) films were deposited on patterned silicon (Si), and silicon nitride (SiN) substrates by pulsed-pressure metal organic chemical vapor deposition (PP-MOCVD) using titanium tetra-isopropoxide (TTIP) as a precursor. The deposition temperature was varied between 400 °C and 600 °C under peak pressure of up to 370 Pa. The surface morphology and thicknesses of the films were examined using a scanning electron microscope (SEM). X-ray diffraction (XRD) was used to analyze the phases of TiO2. The thicknesses of TiO2 films were in the range of 200–350 nm. The phase of thin TiO2 at the deposition temperatures was anatase, exhibiting slight reduction in grain size with increasing temperature. The composition of the films was qualitatively identified by energy dispersive X-ray spectroscopy (EDS). The principal composition of the thin films was TiO2. The conformality of TiO2 films on features was evaluated based on statistical analysis. The step coverage of TiO2 at low temperatures showed a good even coating with a growth rate of more than 20 nm/min. As the temperature increased, the evenness of the coating along a micron-scale step decreased.