Bulk and surface structural properties of Si _1-x-y Ge _x C _y layers processed on Si(001) by pulsed laser induced epitaxy

Si _1-x-y Ge _x C _y films have been grown by pulsed laser induced epitaxy (PLIE) from C ⁺ implanted pseudomorphic Si _1-x Ge _x films and from hydrogenated amorphous a-SiGeC:H films deposited on Si(001). The laser treated samples are examined by electron channelling patterns analysis, X-ray diffraction, channelling Rutherford backscattering spectroscopy and atomic force microscopy (AFM). If laser fluence exceeds a threshold for which the melted zone is thicker than the initial SiGeC layer, the laser induced epitaxy is effective. We show that laser fluence strongly influences germanium profiles. Germanium and carbon atoms are redistributed over the melted depth with a graded profile. Strain profiles, deduced from X-ray dynamical diffraction simulations, exhibit the same gradual evolution from the surface down to the substrate. AFM measurements show a strong decrease of rugosity obtained with suitable PLIE operating conditions.