Proceedings of the third Europeon workshop on Materials for advanced metallization
| Hi-index | 2.88 |
Diffusion barrier properties of Ta films with and without plasma treatments have been investigated in the study. The nitrogen-incorporated Ta films were prepared by NH"3 plasma treatment or reactive sputtering. Barrier properties were evaluated by sheet resistance, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and reverse-biased junction leakage current. An amorphous-like TaN"x layer was formed on Ta barrier film after plasma treatments. The thickness of the amorphous TaN"x layer is about 3nm and NH"3 plasma-treated Ta films (TaN"x/Ta) possess lower resistivity and smaller grain sizes. The Cu/TaN"x/Ta(10nm)/Si remained stable after annealing at 750^oC for 1h. NH"3 plasma-treated Ta films (TaN"x/Ta) possess better thermal stability than Ta and TaN films. It is attributed to the formation of a new amorphous layer on the surface of Ta film after the plasma treatments. For thermal stability of Cu/Ta(-N)/n^+-p diodes, Cu/Ta/n^+-p and Cu/TaN/n^+-p junction diodes resulted in large reverse-bias junction leakage current after annealing at 500 and 525^oC, respectively. On the other hand, TaN"x/Ta diffusion barriers will improve the integrity of Cu/Ta(-N)/n^+-p junction diodes to 650^oC.