Reliability of multistacked tantalum-based structure as the barrier film in ultralarge-scale integrated metallization

Keng Liang Ou, Chi Chang Wu, Chiung Chi Hsu, Chin Sung Chen, Yih Chuen Shyng, Wen Fa Wu

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


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 NH3 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 TaNx layer was formed on Ta barrier film after plasma treatments. The thickness of the amorphous TaNx layer is about 3 nm and NH3 plasma-treated Ta films (TaNx/Ta) possess lower resistivity and smaller grain sizes. The Cu/TaNx/Ta(10 nm)/Si remained stable after annealing at 750 °C for 1 h. NH3 plasma-treated Ta films (TaNx/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 °C, respectively. On the other hand, TaN x/Ta diffusion barriers will improve the integrity of Cu/Ta(-N)/n+-p junction diodes to 650 °C.

Original languageEnglish
Pages (from-to)44-52
Number of pages9
JournalMicroelectronic Engineering
Issue number1
Publication statusPublished - Jul 2005


  • Diffusion barrier
  • Junction diode
  • Plasma treatment
  • Thermal stability

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


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