Reactions of monolayer Fe with Si(001)-dihydride and -2 × 1 surfaces

Reactions between monolayer Fe deposited on Si(001)-2 × 1 and -dihydride surfaces are studied in situ by reflection high-energy electron diffraction and Rutherford backscattering spectrometry with the use of 25 keV hydrogen ions. After room temperature deposition Fe reacts with Si(001)-2 × 1 substrate resulting in the formation of polycrystalline Fe₅Si₃. By annealing to 560-650°C composite heteroepitaxial layers of both type A and type B β-FeSi₂ are formed. On Si(001)-dihydride surface polycrystalline Fe is observed after room temperature deposition, and reaction between Fe and Si(001)-dihydride surface is not likely at RT. After annealing above 700°C 3D rough surface is formed in the case of the dihydride surface. The details of the reaction between monolayer Fe and the dihydride surface are largely different from the reaction between Fe and the 2 × 1 clean surface.