Direct alpha Ta formation on TaN by resputtering for low resistive diffusion barriers

Jung Chih Tsao, Chuan Pu Liu, Ying Lang Wang, Kei Wei Chen

研究成果: Article同行評審

5 引文 斯高帕斯(Scopus)

摘要

The Ta/TaN bilayer exhibits the best performance in the Cu metal multilevel interconnects, because it provides good coherence between Cu and dielectric layer. In the Ta/TaN bilayer, Ta has two phases: alpha-phase of body center cubic is preferred due to its lower resistivity (15-60 μΩ-cm), whereas beta-phase of tetragonal should be avoided due to high resistive (∼150-250 μΩ-cm). However, beta Ta most commonly forms on fee TaN. Here we provide a simple scheme to bypass this high resistive phase by resputtering TaN prior to Ta deposition. We found that, with surface treatment by argon ion bombardment for enough time, alpha Ta phase can be directly formed, which is supported both by X-ray diffraction and resistivity measurement. Depth profiles of all elements from Auger electron spectroscopy reveals that the surface treatment induces a nitrogen deficient surface layer due to different sputtering yield, which causes phase changes from fee TaN to hep Ta 2N followed by bcc Ta(N) and provide a favorable lattice constant for Ta alpha-phase formation.

原文English
頁(從 - 到)2582-2587
頁數6
期刊Journal of Nanoscience and Nanotechnology
8
發行號5
DOIs
出版狀態Published - 2008 5月 1

All Science Journal Classification (ASJC) codes

  • 生物工程
  • 化學 (全部)
  • 生物醫學工程
  • 材料科學(全部)
  • 凝聚態物理學

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