Low temperature proximity gettering of platinum in proton irradiated silicon via interstitial cluster dissociation

Epitaxial silicon samples of n-type have been implanted with 850 keV proton s at a dose of 5x10(13)H(+) cm(-2). Subsequent in-diffusion of platinum at 700 degrees C for 30 min resulted in the presence of a single deep level, w hich is attributed to the platinum acceptor level, at 0.23 eV below the con duction band edge. Depth profiling of this level shows that the substitutio nal platinum is following the vacancy profile in the peak region around the projected range for the protons. In addition, at more shallow depths, a st rong increase of the platinum concentration is also observed. Without ion-i mplantation, no deep levels are detected after in-diffusion at 700 degrees C, while at 800 degrees C, the Pt deep level concentration is inferior to t he one reached after pre-implantation with the above dose. After in-diffusi on at 600 degrees C into the implanted sample, many defects are observed. O ne of these is the substitutional platinum, while the others are considered to be of interstitial nature, due to the fact that their maximum concentra tion is found to be deeper than the projected range of the irradiation, The role of these latter defects in the process of platinum proximity getterin g is discussed. (C) 1999 Elsevier Science B.V. All rights reserved.