In Situ UPS Study of the Formation of FeSi Films from cis-Fe(SiCl3)2(CO)4

Abstract

The chemical vapor deposition (CVD) reaction of cis-Fe(SiCl3)2(CO)4 to form iron silicide, FeSi, has been investigated by in situ photoelectron (PE) spectroscopy in the surface-controlled regime up to 600 °C. The experimental data provide evidence for SiCl4 elimination. The reaction is assumed to occur at the surface via adsorbed silylene complex intermediates. A density functional theory (DFT) calculation approximated for the gas phase shows the elimination of SiCl4 to be endothermic by 15.0 kcal mol-1. The mechanism considered in the calculations involves Cl transfer from Si1 to Si2 of cis-Fe(SiCl3)2(CO)4 accompanied by Fe−Si2 bond fission and formation of [Fe(SiCl2)(CO)4] (calculated energy of activation 47 kcal mol-1, FeSi bond dissociation energy 52 kcal mol-1).