We present a Monte Carlo simulation study for introducing boron ions into Ge in the energy range from 5 to 40 keV. The successful calibration of our ion implantation simulator for crystalline Ge is demonstrated by comparing the predicted boron profiles with SIMS measurements. The generation of point defects are calculated with a modified Kinchin-Pease damage model. An implanted boron profile in Ge is shallower than in Si for any given energy due to the larger nuclear and electronic stopping power of Ge atoms. We found that the higher displacement energy in Ge, the stronger backscattering effect, and the smaller energy transfer from the ion to the primary recoil of a collision cascade are mainly responsible for the significantly reduced damage in Ge