Self ion irradiated Si probed with enhanced depth resolution positron annihilation spectroscopy

Standard positron annihilation spectroscopy (PAS) measurements of implanted Si are limited in the detail that is obtainable on the distribution of the implantation induced defects. In particular, accessing the defect tail distribution is difficult due to the large numbers of defects in the peak concentration and the inherent decrease in depth resolution with increasing positron energy. Enhanced depth resolution positron annihilation spectroscopy overcomes these problems by combining standard positron measurements with the controlled removal of thin layers of the implanted sample. The technique is described in detail and examples of its capabilities are shown using both simulated and experimental (50 keV 5×1013 cm−2, self-implanted Si) data.