Guiding principles toward future gate stacks given by the construction of new physical concepts

Recent LSI technologies require the introduction of a wide variety of materials and structures in addition to conventional aggressive down-scaling. As a result, present semiconductor devices contain various kinds of nano-scale interfaces and nano-structures. In this paper, we show that conventional physics concepts cannot be applied directly to these interfaces or structures and that construction of new physical concepts is crucial for establishing guiding principles toward future LSIs. In fact, we have succeeded in controlling effective gate work functions of high-k gate stacks based on our new interface physics concepts of "Oxygen vacancy induced Fermi level pinning". Moreover, we also propose guiding principles toward future Si nanowire (NW) FET based on atomic and electronic structures of Si NW.