Gold catalyzed nickel disilicide formation: A new solid-liquid-solid phase growth mechanism

Wei Tang*, S. Tom Picraux, Jian Yu Huang, Xiaohua Liu, King-Ning Tu, Shadi A. Dayeh

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

The vapor-liquid-solid (VLS) mechanism is the predominate growth mechanism for semiconductor nanowires (NWs). We report here a new solid-liquid-solid (SLS) growth mechanism of a silicide phase in Si NWs using in situ transmission electron microcopy (TEM). The new SLS mechanism is analogous to the VLS one in relying on a liquid-mediating growth seed, but it is fundamentally different in terms of nucleation and mass transport. In SLS growth of Ni disilicide, the Ni atoms are supplied from remote Ni particles by interstitial diffusion through a Si NW to the pre-existing Au-Si liquid alloy drop at the tip of the NW. Upon supersaturation of both Ni and Si in Au, an octahedral nucleus of Ni disilicide (NiSi 2 ) forms at the center of the Au liquid alloy, which thereafter sweeps through the Si NW and transforms Si into NiSi 2 . The dissolution of Si by the Au alloy liquid mediating layer proceeds with contact angle oscillation at the triple point where Si, oxide of Si, and the Au alloy meet, whereas NiSi 2 is grown from the liquid mediating layer in an atomic stepwise manner. By using in situ quenching experiments, we are able to measure the solubility of Ni and Si in the Au-Ni-Si ternary alloy. The Au-catalyzed mechanism can lower the formation temperature of NiSi 2 by 100 C compared with an all solid state reaction.

Original languageEnglish
Pages (from-to)6009-6015
Number of pages7
JournalNano Letters
Volume13
Issue number12
DOIs
StatePublished - 11 Dec 2013

Keywords

  • homogeneous nucleation
  • in situ TEM
  • liquid mediating
  • Nickel silicide
  • silicon nanowire
  • ternary alloy

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