Laser annealing of silicon on sapphire ion implanted at elevated temperatures

Abstract

Ion implantation doping of silicon on sapphire has been performed with phosphorus and boron ions at target temperatures between 20 and 400°C. After the implantation, a cw Ar ion laser was used for annealing. Both before and after the laser annealing, damage distributions and electrical activity of the dopants were determined by the proton channeling technique and by sheet resistivity measurements, respectively. The combination of ion implantation at an elevated temperature and laser annealing is shown to be a method to reduce the implantation induced damage and stress and also to get a good annealing and high activation level of the dopants. For the as implanted samples, the electrical activation of the dopants was very low and it was necessary to perform an annealing to high temperatures to obtain good activation. For low laser annealing powers, samples implanted at the highest temperatures had higher sheet resistivities than samples implanted at lower temperatures. For sufficiently high laser powers, low sheet resistivities were obtained for all samples.