A deep level transient spectroscopy study of vacancy-related defect profiles in channeled ion implanted silicon

The effect of implantation angle on the profile of vacancy-related defects, represented by the divacancy and vacancy-phosphorus centres, in n-type <100> Cz-Si implanted with 450 keV P or 600 keV Si ions to a dose of 2 × 10^-9 ions·cm^-2 , has been examined using deep level transient spectroscopy depth profiling. Implants were performed with samples aligned with 10° twists from the [110] planar direction and various tilts from the <100> axis. The peak depth of the VP/V₂ profile exhibits a systematic variation with the implantation angle: shifting towards the surface, narrowing and increasing in peak concentration as the implantation angle is progressively varied from the aligned direction. For well-channeled 450 keV P ions, the peak in the defect profile is approximately 0.9 microns deeper than the peak in the vacancy profile predicted using the binary collision codes MARLOWE and Crystal-TCAS. The effect of the surface proximity on defect concentrations has been considered by comparing those profiles obtained for 450 keV P implanted samples with those of 600 keV Si implanted samples.