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 n eeded in the next generation of ultra-large-scale integration technolo gy. 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 spre ading resistance data measured on silicide structures, the interface b etween the silicide and silicon must be precisely located. In this art icle, the use of point-contact current-voltage (PC I-V) measurements f or accurately determining the thickness of ultrathin cobalt silicide-m onocrystalline silicon layers is demonstrated. This method is based on the potential barrier, which exists at the probe/silicon interface, b ut which does not exist at the probe-silicide interface. By monitoring this potential barrier, PC I-V can locate the silicide-silicon interf ace with a resolution of 10 angstrom.