Deactivation of phosphorus in silicon due to implanted nitrogen



Deactivation of phosphorus due to nitrogen incorporation was quantitatively investigated. Coimplantation was performed to produce nitrogen profiles overlapping phosphorus profiles in preamorphized silicon. Nitrogen was found to retard phosphorus activation after recrystallization of the amorphous layer. When phosphorus activation was completed, a gap of dopant activation level was observed between samples implanted with and without nitrogen. The gap of the activation level increased linearly with the doses of nitrogen and phosphorus. This implies formation of inactive complexes by pairing of phosphorus and nitrogen atoms. However, the gap disappeared when the peak profile of nitrogen shifted toward the surface during additional annealing at 750 °C for long times. This indicates that the complexes were not stable and therefore dissolved with nitrogen diffusion. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)