In the last decade ion implantation of common dopants in silicon has been almost full characterised. However, data of inner transition elements are based on few measurements or even extrapolations. Our investigations focus on erbium, an upcoming dopant in photonic applications. Some of us have previously found errors of 20% in the projected range of Er in Si and SiO2 when comparing the range profiles measured with SIMS and simulations using SRIM, T2D, and our own binary collision simulator IMSIL. Because of the far-reaching consequences, we have performed additional, more precise experiments to confirm our previous results. Equal doses of Er has been implanted into SIMOX wafers with energies of 100, 200, 300, 400, 500, and 600 keV. Profiles have been measured with secondary ion mass spectrometry (SIMS). Relative sensitivity factors (RSF) were gathered from low-energy implantations, remaining within the Si top layer. We used the Si/SiO2 interface at exactly 217.7 nm to calibrate the depth scale of all profiles. In addition dynamical Monte-Carlo simulations of the sputter process were taken to correct the depth scale and the interface position. (c) 2005 Elsevier B.V. All rights reserved.