Chemical vapor deposition and characterization of titanium dioxide thin films

The continued drive to decrease the size and increase the speed of micro-electronic Metal-Oxide-Semiconductor (MOS) devices is hampered by some of the properties of the SiO{dollar}sb2{dollar} gate dielectric. This research has focused on the CVD of TiO{dollar}sb2{dollar} thin films to replace SiO{dollar}sb2{dollar} as the gate dielectric in MOS capacitors and transistors. The relationship of CVD parameters and post-deposition anneal treatments to the physical and electrical properties of thin films of TiO{dollar}sb2{dollar} has been studied.; Structural and electrical characterization of TiO{dollar}sb2{dollar} films grown from the CVD precursors tetraisopropoxotitanium (IV) (TTIP) and TTIP plus H{dollar}sb2{dollar}O is described in Chapter 3. Both types of deposition produced stoichiometric TiO{dollar}sb2{dollar} films comprised of polycrystalline anatase, but the interface properties were dramatically degraded when water vapor was added. Films grown with TTIP in the presence of H{dollar}sb2{dollar}O contained greater than 50% more hydrogen than films grown using only TTIP and the hydrogen content of films deposited in both wet and dry TTIP environments decreased sharply with a post deposition O{dollar}sb2{dollar} anneal. A significant thickness variation of the dielectric constant was observed which could be explained by an interfacial oxide and the finite accumulation thickness. Fabricated TiO{dollar}sb2{dollar} capacitors exhibited electrically equivalent SiO{dollar}sb2{dollar} gate dielectric thicknesses and leakage current densities as low as 38, and {dollar}1times10sp{lcub}-8{rcub}{dollar} Amp/cm{dollar}sp2{dollar} respectively.; Chapter 4 discusses the low temperature CVD of crystalline TiO{dollar}sb2{dollar} thin films deposited using the precursor tetranitratotitanium (IV), TNT, which produces crystalline TiO{dollar}sb2{dollar} films of the anatase phase in UHV-CVD at temperatures as low as 184{dollar}spcirc{dollar}C. Fabricated TiO{dollar}sb2{dollar} capacitors exhibited electrically equivalent SiO{dollar}sb2{dollar} gate dielectric thicknesses and leakage current densities as low as 17, and {dollar}1times10sp{lcub}-8{rcub}{dollar} Amp/cm{dollar}sp2{dollar} respectively.; Chapter 5 describes the results of a comparison of physical and electrical properties between TiO{dollar}sb2{dollar} films grown via LPCVD using the precursors tetranitratotitanium(IV) (TNT) vs. tetraisopropoxotitanium (IV) (TTIP). Many film properties grown from TTIP vs. TNT were similar, but the difference in film morphology at low temperature leads to the salient point; that the chemistry of the precursor is important in directing film morphology in the kinetically controlled growth regime.