CoSi2(111), FeSi2(001), and MoSi2(001) Surfaces and Interfaces with Ti

摘要

High-resolution core-level and valence-band photoemission studies of cleavedCobolt silicon(111), FeSi2(001), and MoSi2(001) show that a silicon monolayer terminates the exposed surface. Comparison with results for CoSi2(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/MoSi2(001) compared to Ti/CoSi2(111) and Ti/FeSi2(001) are related to substrate silicide stability. Analysis of the Ti 3p core-level evolution shows equivalent changes for Ti/CoSi2(111) and Ti/MoSi2(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 Angstroms Ti)/CoSi2(111) annealed to 200 C shows increased amounts of TiSi as silicide growth is kinetically enhanced.