The physical and electrical properties as well as thermal stability of
reactively sputtered titanium nitride (TiN) film serving as a diffusion
barrier was studied for silver (Ag) metallization. The thermal stability of
Ag/TiN metallizations on Si with 12-nm-thick TiN barriers, as-deposited and
after annealing at 300-650°C in N2/H2 for 30 min, was
investigated with sheet resistance measurement, X-ray diffraction, focused
ion beam-scanning electron microscopy, atomic force microscopy and X-ray
photoelectron spectroscopy. According to electrical measurement no change of
sheet resistance was found after annealing at 600°C, but an abrupt rise
appeared at 650°C annealing. There are two causes by which the Ag/TiN/Si
structure became degraded. One is agglomeration of the silver layer, and the
other is oxidation and diffusion which are also associated problems during
thermal annealing.