ANOMALOUS CURRENT-VOLTAGE BEHAVIOR IN TITANIUM-SILICIDED SHALLOW SOURCE DRAIN JUNCTIONS

The anomalous behavior of forward and reverse bias current versus applied voltage in titanium-silicided shallow source/drain junctions has been studied. The reverse leakage current characteristics in p+/n shallow junctions (Xj=130 nm) show that the current increases rapidly with titanium thickness and exponentially depends on the reverse bias voltage, while the activation energy of leakage current extracted from the temperature dependence of the current decreases with increasing reverse bias voltage. Forward current in a silicided junction is characterized at low temperatures for the first time. The ideality factor of the forward current increases as temperature decreases and has values higher than 2 at very low temperatures. This behavior cannot be explained by the field-independent Shockley-Hall-Read generation-recombination mechanism. A new mechanism involving the Frenkel-Poole barrier lowering of a trap potential is proposed.