Influence of ultrathin templates on the epitaxial growth of CrSi2 on Si(001)

Structural investigations were performed to analyse the influence of ultrathin silicide layers (templates) on the quality of epitaxial CrSi2 films (thickness of about 40 nm), which were subsequently grown by reactive codeposition on top of these templates. X-ray diffraction and reflectometry, Rutherford backscattering spectrometry (RBS), transmission and scanning electron microscopy were used to characterize orientation, crystalline quality and morphology of the CrSi2 films on Si(001). The templates were formed at a Cr thickness tCr ranging from 0.20 to 1.00 nm. It was shown that reactive codeposition onto templates, grown at 0.35 nm⩽tCr⩽ 0.52 nm, leads to the formation of smooth, homogeneous in thickness epitaxial layers. An RBS minimum yield of about 18% was observed for these samples. The investigation of a thin silicide template (tCr=0.4 nm) has shown that it consists of separated crystallites with two epitaxial orientations: CrSi2(001)[100]∥Si(001)[110] and CrSi2(112)[11¯0]∥Si(001)[110]. The thicker CrSi2 film, grown on top of this template, reproduces its morphology and orientation.