Physical trends of High-k oxides
Conference contribution, 2012
The properties of rare-earth and transition metal oxides of interest for the development of future silicon nanoelectronics will be reviewed. As an introduction, the motivation for using high-k insulators for MOSFET applications will be given together with a basic enlightenment on two crucial intrinsic properties of gate insulators: the dielectric constant, k, and the energy offset value, ∆E, in relation to silicon. It will be demonstrated how these quantities govern initial navigation along metals in the periodic system to find future oxide candidates with feasible leakage characteristics. An overview will be included on the restraining influence of lower-k interlayers, interface states and oxide traps together with a critical survey of existing characterization methods for crucial quantities. Chemical properties like reactivity, structural stability and hygroscopic qualities of interesting oxides will be treated together with reliability issues. Finally, the future challenge of keeping up gate insulator development with the perspectives of the ITRS roadmap will be discussed.