Ion-implanted low-barrier PtSi Schottky-barrier diodes

An ion-implanted, shallow n
⁺
layer has been used for lowering the barrier height of PtSi-n-Si Schottky diodes. Barrier height reductions up to 200 mV have been achieved with little degradation of the diode's reverse-current characteristics. During silicide formation, the implanted ions are "pushed" ahead of the PtSi-Si reaction zone and pile up at the silicide-silicon interface, resulting in more barrier lowering than would be expected from the ion-implant dose. A model including the impurity pileup is presented and calculations based on the model are shown to be in reasonable agreement with experimental measurements.