GROWTH OF SB ON SI(111) STUDIED BY RAMAN-SCATTERING

Sb films up to several hundred monolayers (ML) were prepared in UHV by evaporation onto Si(111) cleaved substrates kept at room temperature. The structure and morphology of the Sb films were monitored in situ b y Raman scattering from the Sb lattice vibrational modes A1g and E(g), from the Si TO-phonon mode and, furthermore, by Auger electron spectr oscopy (AES). Initially, up to approximately 1 ML, the Sb grows as a u niform, smooth layer, whereas above 1 ML island fomation begins. Up to 30 ML the structure of the overlayer is amorphous. At coverages aroun d 30 ML the Sb crystallises in the bulk-like D3d structure. Due to the large lattice mismatch the crystallites are heavily strained. With hi gher film thickness the strain in the film is relieved and the overlay er roughness increases. Additional ex situ Raman experiments were perf ormed to investigate the orientation of these crystallites with respec t to the substrate crystal axes. They demonstrate that the crystallite s are aligned in a well defined orientation with the trigonal axis bei ng nearly perpendicular to the substrate surface.