Collect. Czech. Chem. Commun. 1995, 60, 372-382

Adsorption and Thermal Decomposition of Tetrakis(dimethylamido)titanium on Si and SiO2/Si Surfaces: an XPS Study

Michaela Janovská and Zdeněk Bastl

J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, 182 23 Prague 8, Czech Republic


X-Ray photoelectron spectroscopy (XPS) has been used to study adsorption of tetrakis(dimethylamido)titanium (TDMT) on a clean Si surface and surface on which an oxide layer was grown prior to TDMT adsorption. Measurements were carried out at temperatures 80 and 295 K. In addition, decomposition of TDMT on the above substrates yielding titanium nitride coatings was investigated. The change in surface composition as a function of TiNx layer thickness was monitored by XPS. Adsorption at 80 K proceeds without dissociation on both substrates. Photoelectron spectra measured at 295 K indicate presence of surface species containing C-N multiple bond on both substrates and on SiO2/Si substrate formation of species that contain Ti-N-C rings. At 580 K an overlayer consisting predominantly of TiNx was produced by pyrolysis of TDMT. The photoelectron spectra revealed also presence of species with C-N-C, Si-CHx and Ti-C bonds the concentration of which depended on an overlayer thickness. On SiO2/Si substrate decomposition of SiO2 accompanied by titanium oxide formation occurs during initial stages of TDMT pyrolysis.