Precipitation in silicon-implanted by oxygen and carbon plus oxygen

Abstract

Interest in precipitation processes in silicon appears to be centered on oxygen and carbon impurities in thermally aged materials, and on oxygen implanted materials to form buried dielectric layers. The precipitation reaction products are small, and the presence of carbon is often an important consideration. This abstract reports high resolution electron microscopy observations of precipitate morphology in FZ-Si implanted with oxygen (2.3×l020cm-3 concentration at projected range. Rp). and with oxygen plus carbon (both 1.2×l020cm-3concentration at Rp), and then post-implanted annealed at 923K for 120 hours. These oxygen and carbon concentrations are significantly higher than the saturation oxygen and carbon concentrations in Si at the melting point, which are ∼2×l018 cm-3.After mechanical and argon-ion-milling thinning, (001) wafers were examined in [011] cross-section with an LSI 002B at 200kv for HREM and a Philips EM400ST FEG at l00kv for EELS. A typical implanted region is shown in Fig. 1a for O-implanted and Fig. 1b for O-plus-C-implanted specimens.