Deactivation of Sub-Melt Laser Annealed Arsenic Ultra Shallow Junctions in Silicon During Subsequent Thermal Treatment
Joseph C. Woicik, D. Giubertoni, G. Pepponi, S. Gennaro, M. Bersani, M. A. Sahiner, S. P. Kelty, M. Kah, K. J. Kirkby, R. Doherty, M. A. Foad, F. Meirer, C. Streli, P. Pianetta
The use of non-equilibrium annealing approaches can produce a very high level of arsenic electrical activation in Si but subsequent thermal treatments between 500 and 800 C easily deactivate the dopant to a level one order of magnitude below the solid solubility. In this work, studies about the deactivation of laser annealed (LA) ultra shallow arsenic distributions in silicon using Hall effect measurements, extended x-ray absorption fine structure spectroscopy and secondary ion mass spectrometry are reported. Single crystal Si (100) wafers implanted with As ions at 2 keV energy and different doses were activated with a millisecond LA at 1300 C using a scanning diode laser annealing system under non-melt conditions. The samples were then thermally treated in furnace in a N2 atmosphere for 10 minutes at 300-900C temperatures. Electrical deactivation has been observed, but for the lowest dose; it was observed that the higher the As dose the easier the deactivation, in particular after 700C post-LA treatment. At 900C in-depth diffusion and a relevant re-activation has been observed for samples implanted with 1x1015 and 3x10-15 cm-2.