OISF Pattern and Grown-in Precipitates in Heavily Boron Doped Silicon

Abstract

We study the pattern of oxidation induced stacking faults (OISF) on heavily boron doped silicon wafers. The measured radii of the OISF pattern are compared with simulations and the dependence of the critical value on boron concentration is constructed. The ξ value for undoped silicon is assumed to be close to . The critical value rises steadily with boron concentration following a logarithmic dependency. The OISF ring located in the band, commonly observed in lightly doped silicon, is not detected. We observe the banded OISF pattern, which reflects the residual vacancy profile according to the qualitative model for microdefects formation proposed by Voronkov and Falster [ J. Cryst. Growth , 204 , 462 (1999) ]. Such OISF distribution is not reported so far. As an explanation, abnormal oxygen precipitation during crystal growth due to heavy boron doping and high oxygen content is assumed. Consequently, the grown-in oxygen precipitates, whose density corresponds to the residual vacancy concentration, are stable at the temperature above and serve as the OISF nuclei. Furthermore, we observe fine structure of the band and a strong dependence of the OISF pattern appearance on the oxygen content and the crystal thermal history.