Conduction mechanism in PtSi/Si Schottky diodes

Abstract

The conduction mechanism in PtSi/Si Schottky diodes has been studied in the temperature range of 80 to 300 K. Above 100 K the forward current-voltage (I-V) characteristic of the diodes is highly ideal and obeys the thermionic-emission theory including image-force lowering of the barrier. Certain diodes show a deviation from this behavior, which is due to carrier recombination in the depletion region. Factors that contribute to carrier recombination are a small area-to-periphery ratio and a thick silicide layer. Carrier recombination is also responsible for the soft behavior of the reverse I-V characteristic. The temperature dependence of the barrier height and the bias-independent position of the quasi-Fermi-level at the interface are shown to be associated with a high density of interface states. The activation energy found for the current transport at low temperatures suggests that these states are due to substitutional Pt atoms on the Si lattice.