Tantalum-based diffusion barriers in Si/Cu VLSI metallizations

E. Kolawa, J. S. Chen, J. S. Reid, P. J. Pokela, M. A. Nicolet

Research output: Contribution to journalArticle

220 Citations (Scopus)

Abstract

We have studied sputter-deposited Ta, Ta36Si14, and Ta36Si14N50 thin films as diffusion barriers between Cu overlayers and Si substrates. Electrical measurements on Si n +p shallow junction diodes demonstrate that a 180-nm-thick Ta film is not an effective diffusion barrier. For the standard test of 30-min annealing in vacuum applied in the present study, the Ta barrier fails after annealing at 500 °C. An amorphous Ta74Si26 thin film improves the performance by raising the failure temperature of a 〈Si〉/Ta 74Si26(100 nm)/Cu(500 nm) metallization to 650 °C. Unparalled results are obtained with an amorphous ternary Ta36Si 14N50 thin film in the Si/Ta36Si 14N50(120 nm)/Cu(500 nm) and in the Si/TiSi2(30 nm)/Ta36SiN50(80 nm)/Cu(500 nm) metallization that break down only after annealing at 900 °C. The failure is induced by a premature crystallization of the Ta36Si14N50 alloy (whose crystallization temperature exceeds 1000 °C) when in contact with copper.

Original languageEnglish
Pages (from-to)1369-1373
Number of pages5
JournalJournal of Applied Physics
Volume70
Issue number3
DOIs
Publication statusPublished - 1991

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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