${\mathrm{CoSi}}_2$(111), ${\mathrm{FeSi}}_2$(001), and ${\mathrm{MoSi}}_2$(001) surfaces and interfaces with Ti

High-resolution core-level and valence-band photoemission studies of cleaved ${\mathrm{CoSi}}_2$(111), ${\mathrm{FeSi}}_2$(001), and ${\mathrm{MoSi}}_2$(001) show that a Si monolayer terminates the exposed surface. Comparison with results for ${\mathrm{CoSi}}_2$(111) surfaces prepared by annealing reveals significant differences in surface morphology and Si 2p binding energies. Titanium-atom deposition onto the cleaved surfaces leads to the disruption of the Si monolayer and the appearance of two Ti-induced features that correspond to TiSi-like bonding configurations and Si atoms in solution in the Ti overlayer. Quantitative differences in the distribution of Si in solution for Ti/${\mathrm{MoSi}}_2$(001) compared to Ti/${\mathrm{CoSi}}_2$(111) and Ti/${\mathrm{FeSi}}_2$(001) are related to substrate silicide stability. Analysis of the Ti 3p core-level evolution shows equivalent changes for Ti/${\mathrm{CoSi}}_2$(111) and Ti/${\mathrm{MoSi}}_2$(001), supporting the conclusion that TiSi-like bonding is produced at low Ti coverage. Valence-band spectra show the convergence to Ti metal at high coverage. Analysis of the Si 2p emission for (18 Å Ti)/${\mathrm{CoSi}}_2$(111) annealed to ∼200 °C shows increased amounts of TiSi as silicide growth is kinetically enhanced.