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 (ie, electrically active) B exhibits a negative strain, clustered (ie, 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 (Δ V) induced by ...