Substitutional and clustered B in ion implanted Ge: Strain determination

The lattice strain induced both by substitutional and clustered B in B-implanted Ge samples has been investigated by means of high resolution x-ray diffraction (HRXRD). The main results can be summarized as follows: while substitutional (i.e., electrically active) B exhibits a negative strain, clustered (i.e., electrically inactive) B reverses the lattice strain from negative to positive values, the latter being much higher with respect to those found for clustered B in Si. In particular, the lattice volume modification for each B atom $(ΔV)$ induced by substitutional $(ΔVSub)$ and clustered $(ΔVCl)$ B is $ΔVSub=−12.4Å3$ and $ΔVCl=+14.8Å3$⁠, respectively. These unexpected results demonstrate the ability of HRXRD to quantitatively detect the amount of electrically inactive (and active) B.