Barrier capability of TaNx films deposited by different nitrogen flow rate against Cu diffusion in Cu/TaNx/n+-p junction diodes

Wen Luh Yang, Wen Fa Wu, Don Gey Liu, Chi Chang Wu, Keng Liang Ou

Research output: Contribution to journalArticle

68 Citations (Scopus)

Abstract

This paper investigates the barrier capability of tantalum nitride (TaNx) layers against Cu diffusion. The TaNx layers were reactively sputtered in contact holes to a thickness of 50 nm by using a different nitrogen flow rate. Results indicate that the TaNx layers fail to be a diffusion barrier due to a relative high resistivity for nitrogen flow ratios exceeding 10%. In addition, we found that the phase of α-Ta(-N) functions as an effective barrier against Cu diffusion and that Cu/TaN(3-5%)/n+-p junction diodes are able to sustain a 30 min furnace anneal up to 500 °C without causing degradation of the electrical characteristics. The high-temperature failure of barrier capability for the TaNx layers is due to interdiffusion of Cu and Si across the TaNx film structure to form Cu3Si. The surface roughness and the film structure of TaNx layers determine the ability of Cu and Si interdiffusion.

Original languageEnglish
Pages (from-to)149-158
Number of pages10
JournalSolid-State Electronics
Volume45
Issue number1
DOIs
Publication statusPublished - Jan 1 2001
Externally publishedYes

ASJC Scopus subject areas

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

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