Evaluation of electroless deposited Co(W,P) thin films as diffusion barriers for copper metallization

A. Kohn, M. Eizenberg, Y. Shacham-Diamand, B. Israel, Y. Sverdlov

Research output: Contribution to journalArticlepeer-review

65 Scopus citations

Abstract

Electroless deposited Co(W,P) thin films were evaluated as diffusion barriers for copper metallization. Capacitance versus time measurements of MOS structures as well as SIMS depth profiles indicate that 30-nm-thick films can function as effective barriers against copper diffusion after thermal treatments up to 500 °C. The improved barrier properties relative to sputtered cobalt are explained by the incorporation of phosphorus (8-10 at.%) and tungsten (approximately 2 at.%) which most probably enrich the grain boundaries of the nanocrystalline hcp cobalt grains, forming a `stuffed' barrier. The phosphorus and tungsten additions stabilize the hcp crystalline structure of the cobalt grains, delaying the transition to the fcc phase by more than 80 °C compared to bulk pure cobalt. An advantage of this material compared to alternative diffusion barriers for copper is its relatively low resistivity of 80 μΩ cm.

Original languageEnglish
Pages (from-to)297-303
Number of pages7
JournalMicroelectronic Engineering
Volume55
Issue number1-4
DOIs
StatePublished - 1 Jan 2001
Externally publishedYes

ASJC Scopus subject areas

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

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