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Nucleation and Growth During Tungsten Atomic Layer Deposition on Oxide Surfaces

Published online by Cambridge University Press:  21 March 2011

S. M. George
Affiliation:
Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309 Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO [email protected]
J.W. Elam
Affiliation:
Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309
R.K. Grubbs
Affiliation:
Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309
C.E. Nelson
Affiliation:
Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309
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Abstract

Nucleation and growth has been studied during tungsten (W) atomic layer deposition (ALD) on oxide surfaces. Auger electron spectroscopy (AES) was utilized to examine the deposition of W during the sequential (A) WF6 and (B) Si2H6 reaction cycles that define W ALD. The AES results displayed an initial nucleation period of ∼10 AB cycles to deposit one tungsten monolayer on SiO2. Subsequently, the W and Si AES signals grew and oscillated dramatically versus WF6 and Si2H6 exposures. The increase in the W AES signal in the growth region was consistent with a W ALD growth rate of 3.5 Å per AB cycle. An examination of the oxygen and tungsten AES signals versus AB cycles indicated that W ALD displayed nearly ideal “layer-by-layer”, Frank- van der Merwe growth after the nucleation period. On Al2O3, the AES results displayed a much shorter nucleation period for W ALD. Only 3 AB cycles were required to deposit one tungsten monolayer. Subsequently, the tungsten film grew at a rate of 3.6 Å per AB cycle. The initial nucleation period and growth mechanism during ALD are important because they will affect the roughness of the resulting ALD film.

Type
Research Article
Copyright
Copyright © Materials Research Society 2001

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References

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