A growth rate, structure and surface morphology study of Si1-x-yGexCy films deposited by ArF-LCVD in tilted geometry

摘要

Ge, SiGe, SiC and SiGeC films were grown by ArF-Excimer laser induced chemical vapor deposition. The results demonstrate that in ArF-LCVD a fine and effective control of both the deposition rate, film properties and surface morphology is possible without altering the gas composition and pressure, by changing exclusively the distance between laser beam and substrate surface or by the fact of irradiating or not the films. Different distances have been achieved by tilting the sample 30 degrees with respect to the beam, a geometry simultaneously producing both, an irradiated and a no irradiated zone in the same film. The extensive characterisation of these films was carried out through different techniques in order to see the influence of the irradiation geometry on composition, microstructure and roughness. The evaluation of the deposition rate and the XPS results revealed different growth rate behaviour along the film without considerable variations in composition. AFM proved the small roughness of the films and its strong dependence on the laser beam to substrate distance. Raman spectroscopy and XRD were used to determine the main structural properties. Additional information about surface morphology was also obtained through SEM. For pure Ge, some more studies have been performed due to the tendency of these films to show significant changes, especially in growth rate and roughness, both when the laser irradiated the samples and when temperature, pressure and laser power were varied. (C) 2008 Elsevier Ltd. All rights reserved.