PROFILING OF SILICIDE SILICON STRUCTURES USING A COMBINATION OF THE SPREADING RESISTANCE AND POINT-CONTACT CURRENT-VOLTAGE METHODS

Silicides are increasingly being used as diffusion sources to form the ultra-shallow, low resistance source-drain junctions, which will be needed in the next generation of ultra-large-scale integration technology. The silicide thickness and impurity profile in the silicon must be determined accurately as they are critical parameters in determining the performance of the resulting devices. In order to analyze the spreading resistance data measured on silicide structures, the interface between the silicide and silicon must be precisely located. In this article, the use of point-contact current-voltage (PC I-V) measurements for accurately determining the thickness of ultrathin cobalt silicide-monocrystalline silicon layers is demonstrated. This method is based on the potential barrier, which exists at the probe/silicon interface, but which does not exist at the probe-silicide interface. By monitoring this potential barrier, PC I-V can locate the silicide-silicon interface with a resolution of 10 angstrom.