Thermal Decomposition of Ti(O-iPr)[sub 2](dpm)[sub 2] on a Silicon Surface Analyzed by TPD and XPS

Abstract

The thermal decomposition of titanium diisopropoxide dipivaloylmethanato [: (2,2,6,6-tetramethyl-3,5-heptanedionato, ] on a silicon surface was studied using temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS), and the results were compared with those obtained for a platinum surface. Isopropoxy ligands, which had been dissociated from the Ti precursor and became adsorbed to the silicon surface in the precursor-dosage process, were decomposed to propylene and acetone on the surface at about . Other isopropoxy ligands, which remained bound to the Ti precursor, were decomposed at to produce either propylene and acetone or isopropanol. The dpm ligand was decomposed to propylene at , which was a determinant of the overall rates of Ti-precursor decomposition. was decomposed at higher temperatures by about on the silicon than on platinum, and the major decomposition product was titanium silicate, , on silicon while it was titanium oxide, , on platinum. These different results were obtained because silicon is not as active as platinum for the dissociative adsorption of dihydrogen, which promotes the dissociation of the ligands. The exposure of the silicon surface to prior to the Ti-precursor dosage lowered the temperatures required for the decomposition of the dpm ligand because oxygen, which was chemisorbed on the surface, promoted the dissociation of C–O bonds in the ligand.