EVIDENCE OF AN IMPLANTATION PROCESS IN CARBON DEPOSITION ON SI(100) AT HIGH SUBSTRATE-TEMPERATURE BY LASER-ABLATION

The growth mode of carbon atoms on a clean and reconstructed Si(100) s urface using the laser ablation deposition technique, with the substra te held at high temperature (approximate to 500 degrees C) during depo sition, has been investigated by means of low energy ion scattering sp ectroscopy (ISS), Auger electron spectroscopy (AES), electron energy l oss spectroscopy (EELS) and scanning tunneling microscopy (STM). In co ntrast with the room temperature case, where the mode of growth is lay er-by-layer, evidence for implantation of carbon into the silicon surf ace is found. The implanted C forms a chemically bonded compound at th e sub-surface. STM images of the resulting film show a compacted surfa ce made of clusters with an homogeneous size of around 20 Angstrom dia meter. Moreover, analysis of the secondary ions of the ISS spectra rev eals that the first arriving carbon species from the ablation process produce an important increase of the surface roughness.