ELECTRICAL DEGRADATION OF AL/TIW/COSI2 SHALLOW JUNCTIONS

TiW barrier properties have been investigated by electrical testing of shallow CoSi2 junctions. Rutherford backscattering and Auger analyses have been used to study A1(0.5% Cu)/TiW/CoSi2/Si structure. Based on the electrical data, it was demonstrated that 900 angstrom of TiW will serve as a good diffusion barrier up to 475-degrees-C/30 min. The junctions failed at 450-degrees-C when TiW thickness was reduced to 450 angstrom. The electrical data show the stress of TiW film does not show any significant effects on its properties. Furthermore, shallower junctions (i.e., p+n) are more vulnerable to barrier failure.