Growth of TiO2 thin films on Si(100) substrates using single molecular precursors by metal organic chemical vapor deposition

Growth of titanium dioxide (TiO2) thin films on Si(100) substrates was carried out using a single molecular precursor at deposition temperature in the range of 300–700°C by the metal organic chemical vapor deposition (MOCVD) method. Titanium(IV) isopropoxide, (Ti[OCH(CH3)2]4), was used as a precursor without any carrier gas. Crack-free, anatase type TiO2 polycrystalline thin films with a stoichiometric ratio of Ti and O were successfully deposited on Si(100) at temperature as low as 500°C. XRD and TED data showed the formation of the highly oriented anatase phase with the [211] direction for the TiO2 thin films grown on Si(100) at below 500°C, whereas with increasing the deposition temperature to 700°C, the main film growth direction was changed to be [200], suggesting a possibility of epitaxial thin film growth. Two distinct growth behaviors were observed from the Arrhenius plots. Below 500°C, the growth rate of TiO2 is apparently limited the substrate temperature. The activation energy for TiO2 film deposition calculated in this region is approximately 77.9 kJ/mol, while that for a film grown above 500°C shows a negative value, indicating a predominant diffusion controlled deposition process. Using Al/TiO2/p-Si metal-insulator semiconductor (MIS) diode structure, a dielectric constant was also obtained from a capacitance-voltage (C–V) curve to be 21.