Deposition and characterization of titanium dioxide and hafnium dioxide thin films for high dielectric applications

The industry's demand for higher integrated circuit density and performance has forced the gate dielectric layer thickness to decrease rapidly. The use of conventional SiO₂ films as gate oxide is reaching its limit due to the rapid increase in tunneling current. Therefore, a need for a high dielectric material to produce large oxide capacitance and low leakage current has emerged. Metal-oxides such as titanium dioxide (TiO₂) and hafnium dioxide (HfO₂) are attractive candidates for gate dielectrics due to their electrical and physical properties suitable for high dielectric applications.; MOCVD of TiO₂ using titanium isopropoxide (TTIP) precursor on p-type Si(100) has been studied. Insertion of a TiO _x buffer layer, formed by depositing metallic Ti followed by oxidation, at the TiO₂/Si interface has reduced the carbon contamination in the TiO₂ film. Elemental Ti films, analyzed by in-situ AES, were found to grow according to Stranski-Krastanov mode on Si(100). Carbon-free, stoichiometric TiO₂ films were successfully produced on Si(100) without any parasitic SiO₂ layers at the TiO ₂/Si interface.; Electron-beam deposition of HfO₂ films on Si(100) has also been investigated in this work. HfO₂ films are formed by depositing elemental Hf on Si(100) and then oxidizing it either in O₂ or O ₃. XPS results reveal that with oxidation Hf(4f) peak shifts +3.45eV with 02 and +3.65eV with O₃ oxidation. LEED and AFM studies show that the initially ordered crystalline Hf becomes disordered after oxidation. The thermodynamic stability of HfO₂ films on Si has been studied using a unique test-bed structure of Hf/O₃/Si. Post-Oxidation of Layer Deposition (POLD) has been employed to produce HfO₂ films with a desired thickness. XPS results indicate that stoichiometric HfO ₂ films were successfully produced using the POLD process.; The investigation of the growth and thin film properties of TiO ₂ and HfO₂ using oxygen and ozone has laid a foundation for the application of these metal-oxides into device structures. The novel process involving the TiO_x buffer layer for TiO₂ and the POLD process of HfO₂ have been developed as new processing methods for high dielectric applications.