Reverse annealing of boron doped polycrystalline silicon

Thermal activation was carried out using polycrystalline silicon (poly-Si) produced through sequential-lateral-solidification or excimer-laser-crystallization (ELC) after B+ ion shower doping. The activation efficiency of the ELC samples was found to be higher than that of the SLS ones. In this regard, grain boundaries seemed to play a critical role in terms of the activation of dopants in poly-Si at low temperatures. Reverse annealing, in which a continuous loss of charge carriers occurs, was found in this study at temperatures ranging between 400 °C and 650 °C. The samples treated by rapid thermal annealing showed a lower sheet resistance than those treated by furnace annealing. Rapid thermal annealing was found to exhibit a higher activation efficiency than furnace annealing. Reverse annealing is believed to play an important role in terms of activation efficiency.