Electrical Properties of Silicon Layers Implanted with BF2 Molecules

The annealing behavior of boron in silicon, implanted as BF2 molecules, has been evaluated using Hall-effect and sheet resistivity measurements. For a dose of 1015 cm−2 at room temperature and an anneal at 650°C, the number of carriers/cm2 is increased by a factor of 20 compared to a boron implant. This indicates that an amorphous layer has been formed with this dose, whereas for boron a dose of≥2×1016 cm−2 is required. For doses ≤1014 cm−2, there is no marked difference in the annealing of BF2 and boron implants concerning majority carriers characteristics of the implanted layers.