Low temperature tunneling current enhancement in silicide/Si Schottky contacts with nanoscale barrier width

The low temperature electrical behavior of adjacent silicide/Si Schottky contacts with or without dopant segregation is investigated. The electrical characteristics are very well modeled by thermionic-field emission for nonsegregated contacts separated by micrometer-sized gaps. Still, an excess of current occurs at low temperature for short contact separations or dopant-segregated contacts when the voltage applied to the device is sufficiently high. From two-dimensional self-consistent nonequilibrium Green's function simulations, the dependence of the Schottky barrier profile on the applied voltage, unaccounted for in usual thermionic-field emission models, is found to be the source of this deviation.