Formation of silicon ultra shallow junction by non-melt excimer laser treatment

Abstract

Implementation of plasma doping and nanosecond laser annealing in the non-melt regime has shown to hold great promise for the realization of ultra shallow junctions, designed for the sub 45 nm node. This work includes extensive simulation of these two emerging techniques using the Synopsys Sentaurus Process software tool, in direct comparison with experimental data for each step involved in the process. Analytical calculations were performed in order to investigate the interaction of the KrF Excimer Laser Annealing and silicon regarding the temperature gradients induced into silicon and the boron diffusion kinetics. On the other hand, analytically obtained surface temperature profiles of each annealing condition, were used as input to KMC calculations of the boron diffusion and activation behavior. Simulation predictions, in accordance with SIMS measurements revealed very limited dopant profile movement (maximum 2.5 nm), combined with high levels of electrical activation close to the maximum theoretically predicted ones. As the results obtained by calculations are in consistency with the experimental, it is evident that the combination of both analytical and Kinetic Monte Carlo tools, allows for sufficient physical understanding of the underlying mechanisms for these advanced process steps.