Plasma immersion ion implantation of nitrogen in Si: formation of SiO 2, Si 3N 4 and stressed layers under thermal and sputtering effects

Abstract

Plasma immersion ion implantation (PIII) of nitrogen in silicon (Si) wafers was carried out using a dc glow discharge plasma source and a hard tube pulser. Ion irradiation times ranging from 3 to 60 min were used to accumulate different doses. Surface analysis of these samples was carried out by Auger electron spectroscopy (AES), revealing a high atomic concentration of nitrogen (up to 60%) in the as-implanted Si wafer, besides the presence of different impurities as oxygen and carbon in significant quantities. Depth profiles of these elements were obtained as well as of compound species as SiO 2 and Si 3N 4, using this high-energy resolution AES. Comparing the concentration profiles of implanted nitrogen in Si and the corresponding retained doses in these samples, it was possible to understand the thermal and sputtering effects in our present PIII experiment. High-resolution XRD results corroborate the formation of highly stressed layers in the as-implanted substrates. These experimental results are compared to simulations obtained by TRIDYN code.