Pile up of implanted phosphorus during palladium silicide formation and the characteristics of Schottky barrier diodes

Schottky barrier diodes are fabricated on silicon surfaces whose impurity concentrations are controlled by ion implantation of phosphorus. The barriers are produced from Pd2Si or Al–Si. The forward voltages of Schottky barrier diodes made from Pd2Si show a much greater lowering than those made from Al–Si for implanted doses of 5×1013 cm−2 and higher. Spreading resistance measurements show that the implanted phosphorus atoms are piled up at the Pd2Si–Si interface during Pd2Si formation. This causes reduction in the effective barrier height.