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Tantalum-based diffusion barriers in Si/Cu VLSI metallizations

Kolawa, E. and Chen, J. S. and Reid, J. S. and Pokela, P. J. and Nicolet, M.-A. (1991) Tantalum-based diffusion barriers in Si/Cu VLSI metallizations. Journal of Applied Physics, 70 (3). pp. 1369-1373. ISSN 0021-8979. http://resolver.caltech.edu/CaltechAUTHORS:KOLjap91

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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>/Ta74Si26(100 nm)/Cu(500 nm) metallization to 650 °C. Unparalled results are obtained with an amorphous ternary Ta36Si14N50 thin film in the Si/Ta36Si14N50 (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.


Item Type:Article
Additional Information:Copyright © 1991 American Institute of Physics. Received 22 February 1991; accepted 19 April 1991. The authors wish to thank R. Gorris and B. Stevens for technical assistance, R. Ruiz of the Jet Propulsion Laboratory for SEM analyses and R. Sampley for assistance in manuscript preparation. This work was sponsored in part by the Army Research Office under subcontract DAAL03-89-K-0049, whose support is acknowledged. A graduate fellowship award by the AMOCO foundation is gratefully acknowledged by J. S. Reid, and P. J. Pokela thanks the Academy of Finland for a fellowship.
Subject Keywords:TANTALUM; TANTALUM SILICIDES; TANTALUM NITRIDES; THIN FILMS; SPUTTERING; JUNCTION DIODES; VLSI; ELECTRICAL PROPERTIES; COPPER; METALLIZATION; AMORPHOUS STATE; RUTHERFORD SCATTERING; X–RAY DIFFRACTION; TRANSMISSION ELECTRON MICROSCOPY; DIFFUSION BARRIERS
Record Number:CaltechAUTHORS:KOLjap91
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:KOLjap91
Alternative URL:http://dx.doi.org/10.1063/1.349594
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3915
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:19 Jul 2006
Last Modified:26 Dec 2012 08:56

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