Observation of heterostructure epitaxy of Pt-doped Ni-monosilicide on Si(001)

Abstract The objective of this study was to determine detailed microstructure of a Ni 1– x Pt x Si film formed via a melting/quenching process using high temperature laser annealing on a Si(001) substrate. The orthorhombic Ni 1– x Pt x Si film was found to be able to epitaxially grow with a crystallographic relationship of Ni 1– x Pt x Si[010]//Si[110], Ni 1– x Pt x Si(400)//Si(3 3 ¯ 1), and Ni 1– x Pt x Si (104)//Si(004). Volume expansion of the Ni 1– x Pt x Si film due to Pt incorporation was mainly accommodated by an increase in only one direction nearly parallel to the film surface (lattice parameter a ). This was explained by the minimum coherent strain at the Ni 1– x Pt x Si (104)/Si(004) interface with an epitaxial growth tendency. Atomic-scale scanning transmission electron microscopy analyses revealed that the interface of Ni 1– x Pt x Si/Si had a repetitive atomic-step feature with energetically favorable Ni 1– x Pt x Si(004) terraces and (400) structural ledges that could increase the coherent area. By generating an array of misfit dislocations with an extra half plane of Ni 1– x Pt x Si(020), the elastic strain was further relieved.