Boron ions in the 15–50 MeV energy range were implanted into high resistivity silicon targets. The range distributions were measured by Spreading Resistance Profilometry (SRP) and for the first time by Secondary Ion Mass Spectrometry (SIMS). The two techniques provide accurate range and straggling experimental determinations even at this large depth (∼ 100 μm). The carrier profile matches quite well the chemical profile in all the investigated samples. The profiles are characterized by a long front tail at low boron concentration due to single scattering events at large angle. The distribution around the peak is broaded by electronic straggling and in some cases by channeling effects. This latter phenomenon introduces an asymmetry around the peak. The Bethe approach in combination with large angle scattering and electronic straggling describes the profiles.