Electron energy-loss spectrum imaging of high-k dielectric stacks

Spectrum imaging combined with electron energy-loss spectroscopy is a powerful technique that can be used to examine the structural, chemical and electronic properties of materials on a subnanometer scale. We have applied this technique to investigations of high-k dielectric stacks and report results obtained from a HfO2∕HfSiO stack on Si. The results provide insight into the spatial distribution of the HfO2 and SiOx phases that result from decomposition of metastable “HfSiO.” Some of the HfO2 is observed to penetrate into the poly-Si gate electrode material.