Er-O clustering and its influence on the lattice sites of Er in Si

We present emission channeling experiments on the lattice location of Er in CZ Si single crystals with a well-defined O concentration of 6.5-6.6 $\times 10^{17}$ cm$^{-3}$ and 60 keV-implanted Tm+Er doses ranging from 4.3 $\times 10^{12}$ cm$^{-2}$ to 3.6 $\times 10^{13}$ cm$^{-2}$. The experimental results are compared to the predictions of a simulator which models the formation of Er$_{n}$O$_{m}$ clusters on the basis of simple diffusion and capture kinetics. We find that our experimental data compare favorably with a scenario where the formation of Er$_{n}$O$_{m}$ defects with one or more O atoms is responsible for removing the Er atoms from their tetrahedral interstitial (T) sites. This suggests that Er does no longer occupy the T site even in simple (ErO) pairs.