Rutherford backscattering/channeling analysis was used to study the damage creation processes occuring during 1 MeV O+ implantation in silicon. The target temperature was varied from RT to 500°C using beam heating. The corresponding damage profiles and dechanneling behaviour were studied. Several implantations were performed at 77K for comparison. Transmission electron microscopy observations were connected to the dechanneling measurements in order to determine the dominant kind of defect in each case.
For 77K implants, the defects are mainly interstitials distributed according the energy deposition in elastic collisions, extending up to the surface. At 500°C, the defects are imperfect dislocations confined in a narrow band around the mean range of oxygen ions. We demonstrate that dechanneling in samples implanted at intermediate temperatures results from a mixing of point defects and distorsion centers. The relative importance of the two kind of defects is followed as a function of implantation temperature.