Ti-capping and heating ramp-rate effects on Ni-silicide film and interface

Abstract

The effects of oxygen in metal, Ti capping and heating ramp rate on Ni-silicide formation and Ni-silicide/Si interface have been studied. The oxygen in Ni film results in high resistivity of Ni-silicide film, poor thermal stability, and poor electrical interface. Ti-capped silicidation can scavenge oxygen onto the silicide surface and results in comparable low resistivity, high thermal stability Ni-silicide film as that formed by oxygen-free deposition. The temperature-dependent current-voltage measurement of the Ni-silicide Schottky barrier diodes (SBD) with and without Ti capping reveals that both contacts have strip-like inhomogeneity and the inhomogeneity is larger for the SBD without Ti capping. Different heating ramp rate in Ni-silicidation has almost no effect on Ni-silicide film itself. But the electrical quality of Ni-silicide/Si interface is significantly influenced by the ramp rate. High ramp-rate (24/spl deg/C) heating gives rise to a poor Ni-silicide/Si interface, compared to low ramp-rate (12/spl deg/C) heating.