Investigation of CxSi defects in C implanted silicon by transmission electron microscopy

Buried CxSi layers were produced by high-energy implantation of carbon into CZ silicon. The depth distribution of carbon, the morphology of the buried layers, as well as the precipitation of C were investigated as functions of rapid thermal annealing between 700 and 1300 °C, using transmission electron microscopy, secondary ion mass spectroscopy, and positron annihilation measurements. Different kinds of microdefects occur: below ≈800 °C there are vacancy agglomerates as well as metastable C–Si agglomerates (Φ≈2 nm), whereas at higher temperatures β-SiC precipitates are observed. Results are discussed in terms of the interaction between C atoms and radiation-induced defects.