| As the gate length in field effect transistors continues to decrease the thickness of the SiO2 gate oxide must also be scaled. Within the next decade this trend reaches an abrupt limit at ∼1.5 nm where tunneling leads to unacceptable leakage currents. One solution is to replace the current SiO2 gate oxide with a material possessing a higher dielectric constant (κ). This thesis describes the chemical vapor deposition (CVD) of potential alternate gate oxides. The first project involved the CVD of thin films of ZrO2 and HfO2 from anhydrous Zr(NO 3)4 and Hf(NO3)4. Films were characterized by Rutherford backscattering (RBS), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), medium energy ion scattering (MEIS), and Xray photoelectron spectroscopy (XPS). In the second part of the thesis, the CVD of amorphous TixSi1−xO 2 films from Si(OC2H5)4 and either Ti(OCH(CH3)2)4 or anhydrous Ti(NO3) 4 is described. The composition of the films depended upon the choice of TiO2 precursor. Explanations for the observation of precursor-controlled stoichiometry are outlined and discussed. The final project presented describes the development of combinatorial CVD techniques. Continuous compositional spreads of the TiO2-SnO2HfO2 ternary system were deposited onto a single Si substrate using the corresponding nitrate precursors. Film characterization (RBS, XPS, XRD) and electrical characteristics (C-V, IN) were mapped relative to position within the sample. Using these combinatorial CVD methods, compositions in the TiO2-SnO2-HfO 2 system were identified that possessed a high value of κ. Additionally, the presence of a unique composition (Hf0.69Sn0.31O 2) that crystallizes in the orthorhombic α-PbO2 phase was observed. |
