Dopants (P, As, and B) in the polycrystalline silicon/titanium silicide system: Redistribution and activation

In this work we report, for the first time, a comparative experimental study of dopant loss from heavily doped polycrystalline silicon (polysilicon) into overlying titanium silicide due to postsilicidation heat-treatments. The experimental study examines the impact of furnace annealing (750 to 1050°C) and rapid thermal processing for the dopant types phosphorus, arsenic, and boron. The effect of wafer thermal history on percentage activation of dopants in polysilicon is also presented. These results provide a more detailed understanding of polysilicon depletion effects in metal oxide semiconductor field effect transistors and of contact phenomena related to dopant loss and dopant deactivation at the polycilicon/silicide contact.