Oxide growth retardation induced by rapid thermal annealing in Czochralsky-grown silicon consequence on the efficiency and the stability of internal gettering of Cr

The anomalies induced by rapid thermal annealing (RTA) on the behavior of o xygen and their consequences on the efficiency and the stability of interna l gettering of chromium in Czochralsky-grown silicon have been studied. Dee p level transient spectroscopy profiling of the electrically active Cr conc entration on bevelled samples, transmission electron microscopy observation s on cross-sectional specimens, oxygen precipitate density assessment by et ch pits counting and interstitial oxygen concentration measurements using F ourier transform infrared spectroscopy are presented. We have observed that the metal precipitation is controlled by the oxygen precipitation, and est ablished a correlation between the internal gettering efficiency and the mo rphology of oxygen precipitates after nucleation. Besides, we have shown th at the thermal instability of metallic precipitates strongly depends on the size and the morphology of oxygen precipitates at the end of the gettering treatment. Finally, our results support the concept of 'oxygen-precipitati on gettering' previously reported by Gilles and Weber in the case of iron [ D. Gilles, E.R. Weber, Phys. Rev. Lett. 64 (1990) 196.], and suggest the in volvement of a dynamic effect, linked to the metallic precipitate growth wh ich is triggered by emission of interstitial silicon during the growth of t he oxygen precipitates. (C) 2000 Elsevier Science B.V. All rights reserved.