Investigation of Surface Segregation Phenomenon in Thin Films

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Ahadian, Mohammad Mahdi | 2006

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Type of Document: Ph.D. Dissertation
Language: Farsi
Document No: 40709 (04)
University: Sharif University of Technology
Department: Physics
Advisor(s): Iraji zad, Azam
Abstract:
In this thesis, substrate surface segregation during thin film deposition and also during heat treatment has been investigated. For this purpose, surface segregation of copper substrate has been studied in some thin layer systems and the results revealed that surface segregation is possible in more unexpected situations. Complete studies of Ni/Cu system were investigated in UHV condition and direct measurement of surface energy as the main controlling parameter of surface segregation was done using contact angle measurements. The results indicated that in V2O5/Cu system, surface segregation of the Cu occurred up to oxide thickness of 200 nm. The Cu surface segregation in the electrodeposited Ni-Fe (Permally) and Ni layers onto Cu substrate indicated that more accumulation of Cu occurred than similar vacuum deposited samples and this phenomenon was observed up to micrometer thickness. As the experimental results indicate, existing models for surface segregation during deposition are not adequate and an extended model has been proposed based on KTBIM approach. Also a description of surface segregation in electrodeposition bath has been suggested for the first time
Keywords:
Surface Segregation ; Heat Treatment ; Thin Films ; Surface Accumulation ; Surface Energy