Amorphous Ta-nanocrystalline RuOx diffusion barrier for lower electrode of high density memory devices

Dong Soo Yoon, Hong Koo Baik, Sung Man Lee, Jae Sung Roh

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


The effects of the amount of RuO2 added in the Ta film on the electrical properties of a Ta-RuO2 diffusion barrier were investigated using n++-poly-Si substrate at a temperature range of 650-800°C. For the Ta layer prepared without RuO2 addition, Ta2O5 phase formed after annealing at 650°C by reaction between Ta and external oxygen, leading to a higher total resistance and a non-linear I-V curve. Meanwhile, in the case of the Ta film being deposited with RuO2 incorporation, not only a lower total resistance and ohmic characteristics exhibited, but also the bottom electrode structure was retained up to 800°C, attributing to the formation of a conductive RuO2 crystalline phase in the barrier film by reaction with the indiffused oxygen because of a Ta amorphous structure formed by chemically strong Ta-O or Ta-Ru-O bonds and a large amount of conductive RuO2 added. Since a kinetic barrier for nucleation in formation of the crystalline Ta2O5 phase from an amorphous Ta(O) phase is much higher than that of crystalline RuO2 phase from nanocrystalline RuOx phase, the formation of the RuO2 phase by reaction between the indiffused oxygen and the RuOx nanocrystallites is kinetically more favorable than that of Ta2O5 phase.

Original languageEnglish
Article number89
Pages (from-to)493-502
Number of pages10
JournalJournal of Electronic Materials
Issue number5
Publication statusPublished - 2001 May

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry


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