Enhancement of depth sensitivity in slow positron implantation spectroscopy of Si

Information gained by non-destructive slow positron implantation spectrosco py on the depth distribution of open-volume defects created by ion implanta tion in Si is limited. In particular, determination of the shape of defect tails is hampered by the dominance of the positron response to defects in t he peaked subsurface distribution and the unavoidable decrease in depth res olution as the incident positron energy increases and the positron implanta tion profile broadens. Enhanced depth resolution is achieved by combining s tandard positron-beam-based Doppler broadening spectroscopy with controlled removal of thin layers of the implanted sample by anodic oxidation and etc hing. The technique is described in detail and examples of its capabilities are shown using both simulated and experimental data. (C) t999 Elsevier Sc ience B.V. All rights reserved.