Ion-beam-induced crystallization of carbon-implanted silicon studied by auger electron spectroscopy

Abstract

The influence of high-energy Si+ irradiation on carbon-implanted silicon at low temperature was studied. C+ Ions of kinetic energy 25 keV were implanted into Si(100) at room temperature with a dose density of 1×1017 ions cm−2 after amorphization of the surface region by Ge+ implantation at 200 keV. Subsequently, the amorphous and substoichiometric silicon–carbon matrix was subjected to a bombardment with 300 keV Si+ at 400°C to generate ion-beam-induced epitaxial crystallization. Rutherford backscattering spectroscopy combined with channelling disclosed the migration of the recrystallization front from the underlying amorphous silicon substrate up to the carbon-rich layer in dependence on the Si+ dose. Auger electron spectroscopy (AES) in combination with rotational sputter depth profiling provided detailed information about the depth-dependent composition, the different chemical states of the elements and the synthesized phases. The electron spectra reveal SiC phase formation with a corresponding electron density derived from plasmon energy losses. The plasmon-loss features in the Si LVV and KL23L23 spectra indicate the presence of fine-dispersed silicon carbide precipitates of average size ∽0.5–3 nm in a silicon–carbon matrix. Although a beneficial effect of Si+ irradiation on crystallization of the entire implantation zone could not be observed for dose densities ⩽1×1017 ions cm−2, this study demonstrates the successful application of AES for the characterization of heterogeneous materials with embedded nanoparticles in the matrix. © 1998 John Wiley & Sons, Ltd.