The growth mode of carbon atoms on a clean and reconstructed Si(100) surface using the laser ablation deposition technique, with the substrate held at high temperature ( 500°C) during deposition, has been investigated by means of low energy ion scattering spectroscopy (ISS), Auger electron spectroscopy (AES), electron energy loss spectroscopy (EELS) and scanning tunneling microscopy (STM). In contrast with the room temperature case, where the mode of growth is layer-by-layer, evidence for implantation of carbon into the silicon surface is found. The implanted C forms a chemically bonded compound at the sub-surface. STM images of the resulting film show a compacted surface made of clusters with an homogeneous size of around 20 diameter. Moreover, analysis of the secondary ions of the ISS spectra reveals that the first arriving carbon species from the ablation process produce an important increase of the surface roughness.