The boron diffusion in three kinds of group IV semiconductors: silicon, silicon carbide and synthetic diamond has been studied by secondary ion mass spectrometry. Ion implantation of 300 keV, 11B-ions to a dose of 21014 cm-2 has been performed. The samples are subsequently annealed at temperatures ranging from 800 to 1650 °C for 5 minutes up to 8 hours. In silicon and silicon carbide, the boron diffusion is attributed to a transient process and the level of out-diffusion is correlated to intrinsic carrier concentration. No transient, out-diffused, boron tail is revealed in diamond at these temperatures.