Nanostructured surfaces

Phase formation and structure of the Cu thin ﬁlm interlayer on Si(111) substrate: a molecular dynamics simulation study 
V. Plechystyy1,2, I. Shtablavyi2, S. Winczewski1, K. Rybacki1, S. Mudry2, J. Rybicki1

1 Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdansk, Poland.

2 Physics of Metals Department, Ivan Franko National University of Lviv, Kyrylo i Mephodiy 8, 79005 L’viv, Ukraine 
E-mail: ihor.shtablavyi@lnu.edu.ua,

With the development of ultra-large scale integrated circuits Cu has been gradually used as interconnection material to replace Al due to its low resistivity and high electron migration resistance. This replacement results in the research interests of growth of Cu thin ﬁlm on Si substrate. In contrast to the system of aluminum-silicon, in the Cu-Si system the formation of several compounds is possible. In recent years, silicides have been extensively used as device contact and interconnect. Interest in Cu as interconnect has generated the need of understanding the reactions between Cu and silicon, the structures of the Cu films deposited, and the reactions between Cu and silicide contacts. 
Currently, there is little studies dedicated the kinetics of processes occurring at the interface of liquid and crystalline phases. The processes of phase formation, in this case, are quite fast and, respectively, are complicated for experimental investigation. Experimental methods allow us to determine only the result of the interaction of liquid and crystalline phases and do not provide information about the features of this interaction at different instant of time. 
Therefore, a computer simulation of the formation of the interphase boundary in the copper-silicon system was carried out in this work and the transformation of the structure for this system at different temperatures has been investigated. In addition, the differences in the structure of the bulk liquid alloy with the melts on the boundary of copper and silicon were analyzed.