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Cu surface segregation in Ni/Cu system

Rasuli, R ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1016/j.vacuum.2009.10.009
  3. Abstract:
  4. We report experimental evidence of Cu surface segregation in Ni/Cu system, during deposition of Ni film onto Cu substrate at room temperature and during heat treatment in vacuum. Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) by Tougaard's analysis results show that surface segregation defeats in competition with increase in Ni thickness and terminates when thickness of Ni increase to more than 4 nm. Surface energy and concentration were calculated using contact angle measurements and the results confirm that segregation reduces the surface energy. Surface segregation during heat treatment at 150-220 °C range as a function of time initially shows linear mass transfer. By solving Fick's equation and taking empirical diffusion coefficient, 125 ± 20 kJ/mol is obtained for activation enthalpy of effective diffusion
  5. Keywords:
  6. Diffusion ; Nickel ; Surface segregation ; X-ray photoelectron spectroscopy ; Activation enthalpies ; Analysis results ; Copper diffusion ; Cu substrate ; Diffusion coefficients ; Effective diffusion ; Experimental evidence ; Fick's equation ; Function of time ; In-vacuum ; Ni films ; Nickel surfaces ; Room temperature ; Surface energies ; Angle measurement ; Augers ; Contact angle ; Copper ; Electrons ; Heat treatment ; Interfacial energy ; Nickel alloys ; Photoelectricity ; Photoionization ; Photons ; Segregation (metallography) ; Surface chemistry ; Surface tension ; Thermal effects ; Vacuum deposition ; Auger electron spectroscopy
  7. Source: Vacuum ; Volume 84, Issue 4 , 2009 , Pages 469-473 ; 0042207X (ISSN)
  8. URL: http://www.sciencedirect.com/science/article/pii/S0042207X09004680