The ability to follow Moore's Law 1 has been the basis of the tremendous success of the semiconductor industry in the past decades. To date, the greatest challenge for device scaling is the required replacement of silicon dioxide-based gate oxides by high-k oxides in transistors. Around 2010 high-k oxides are required to have an atomically defined interface with silicon without any interfacial SiO 2 layer. The first clean interface between silicon and a high-K oxide has been demonstrated by McKee et al. 2 Nevertheless, the interfacial structure is still under debate. Here we report on first-principles calculations of the formation of the interface between silicon and SrTiO 3 and its atomic structure. Based on insights into how the chemical environment affects the interface, a way to engineer seemingly intangible electrical properties to meet technological requirements is outlined. The interface structure and its chemistry provide guidance for the selection process of other high-k gate oxides and for controlling their growth. Our study also shows that atomic control of the interfacial structure can dramatically improve the electronic properties of the interface. The interface presented here serves as a model for a variety of other interfaces between high-k oxides and silicon.According to the International Technology Roadmap for Semiconductors 3 , gate oxides shall be scaled to a thickness below 1.5 nm as early as 2005. This corresponds to only a few atomic layers. Due to the quantum mechanical tunneling effect, electrons can pass directly through such a thin layer of an insulating material resulting in large static power consumption. Since about five years ago, intense research has been performed to replace silicon dioxide related materials with other oxides that have a higher dielectric constant (high-k). This would allow the use of a thicker gate oxide while retaining the electrical properties of an ultrathin

This paper reports state-of-the-art electronic structure calculations on the deposition of strontium on the technologically relevant, (001) orientated silicon surface. We identified the surface reconstructions from zero to four thirds monolayers and relate them to experimentally reported data. A phase diagram is proposed. We predict phases at 1/6, 1/4, 1/2, 2/3 and 1 monolayers. Our results are expected to provide valuable information in order to understand heteroepitaxial growth of a prominent class of high-K oxides around SrTiO3. The insight obtained for strontium is expected to be transferable to other alkaline earth metals

Ϫ are found to be particularly stable. Theoretical density functional calculations on neutral and anionic Al n N (nϭ1-8) clusters were performed and the stability and reaction energetics with oxygen examined. Clusters requiring less than 5.7 eV to remove an electron and an Al atom are shown to be resistant to the reaction with oxygen.

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