Thermal Stability of Cu / CoSi2 Contacted p+n Shallow Junction with and without TiW Diffusion Barrier

Abstract

The thermal stability of contacted p+n shallow junction diodes with and without diffusion barrier was investigated with respect to metallurgical reaction and electrical characteristics. Without the diffusion barrier, the (with a junction depth of 0.2 μm measured from the silicide surface) were able to sustain a 30 s rapid thermal annealing (RTA) in ambient up to 450°C without losing the integrity of the devices characteristics. The phase was observed at the interface after 500°C annealing; the phase penetrated through the layer causing a catastrophic change in layer structure after 700°C annealing. With the addition of a 1200 Å thickness of diffusion barrier between Cu and , the junction diodes were able to sustain the RTA treatment up to 775°C without degrading the basic electrical characteristics, and no metallurgical reaction could be observed even after an 800°C annealing.