Sheet resistance and Hall measurements have been made on boron layers implanted into [Formula: see text] and [Formula: see text] silicon at energies between 15 and 60 KeV. The features of the annealing curves are discussed. Hall measurements indicate that the large reverse annealing effect observed in several samples implanted at room temperature is due to a rapid fall off in the density of an acceptor level between annealing temperatures of 400 and 600 °C. It is suggested that this level is associated with substitutional boron.Conducting layers formed by implants at high doses (6 × 1015 cm−2) and low annealing temperatures are shown to be sensitive to specimen temperature during implantation and dose rate. This sensitivity is associated with the formation of an amorphous layer.The conductivity of layers implanted at temperatures of 400–500 °C is shown to be lower than corresponding room temperature implants followed by annealing.