Electronic structure of Silicide - Silicon interfaces

Significant understanding of the processes occurring at the interface between transition metal ultra thin overlayers and silicon has been achieved in recent years. In general these interfaces are highly reactive and the formation of an interfacial silicide compound takes place. The reaction at the near-noble metal- silicon interface can occur even at liquid nitrogen temperature. Furthermore the reaction products can give rise to epitaxial interfaces. Haw can the covalent bonds in silicon be broken at such a low temperature and eventually give rise to an epitaxial interface are intriguing questions, which cannot be answered without a full understanding of the electronic and atomic processes involved in the interface reaction. Theoretical investigation through band structure calculations allows us to understand the modifications of the silicide electronic states in the interface region. Assuming various interface geometries /e.g. epitaxial growth or interstitial interdiffusion) the effect of different atomic processes on the electronic properties is analysed and available photoemission and Auger spectroscopic experimental information are interpreted. The role of both electronic states and atomic processes in determining the interface physical properties is discussed.