COMPARISON OF THE DIFFUSION BARRIER PROPERTIES OF CHEMICAL-VAPOR-DEPOSITED TAN AND SPUTTERED TAN BETWEEN CU AND SI

This work investigated the barrier properties of metalorganic chemical -vapor-deposited (CVD) tantalum nitride (TaN) and physical-vapor-depos ited (PVD) TaN between Cu and Si. The CVD TaN film had a preferred ori entation (200) with a grain size of around 60 nm, while the PVD TaN ha d a (111) preferred orientation with a grain size of around 20 nm, as determined by transmission electron microscopy (TEM) and x-ray diffrac tion (XRD) analyses. Degradation study of the Cu/TaN/Si contact system was also performed by sheet resistance measurement, scanning electron microscopy (SEM), XRD, secondary ion mass spectroscopy (SIMS), and sh allow junction diodes. These results indicated that the PVD TaN film c an act as a better diffusion barrier than the CVD TaN film. The higher thermal stability of PVD TaN than CVD TaN can be accounted by their d ifference in microstructures. The failure mechanisms of both CVD TaN a nd PVD TaN films as diffusion barriers between Cu and Si were also dis cussed. (C) 1996 American Institute of Physics.