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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


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
Issue number1-4
StatePublished - Mar 2001


FundersFunder number
Israel Ministry of Science and Technology


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