Ion scattering studies of high-K gate stacks: thermal stability and interdiffusion

Abstract

Format

This is a copy of the slides presented at the meeting but not formally written up for the volume.

Abstract

To enable the selection of appropriate novel materials in nano-electronics, the ultrathin film and interface properties of adjoining materials must be understood at the atomic scale. A wide range of chemical stability and electronic structure issues need to be understood to allow the integration of high-κ dielectrics and metal electrodes in nanoscale CMOS. We will present results on the structure and composition of two different classes of potentially interesting high-κ materials, mainly obtained with medium energy ion scattering (MEIS), a high-resolution, low energy version of Rutherford Backscattering (RBS). We will discuss amorphous or polycrystalline films of materials such as HfO₂, ZrO₂, Y₂O₃, etc and present data on their thermal stability and reactivity to adjoining semiconducting channel and gate electrode materials. We will also discuss recent results on the use of isotopically labeled oxygen to learn about how oxygen reacts with and exchanges in the films, as oxygen chemistry appears critical to understanding defects in these systems. Additionally, results on the stability of ultrathin dielectrics on alternative channel materials (Ge and GaAs) will be presented.SRC, Sematech, NIST and NSF are gratefully acknowledged for their financial support.