Combined spectroscopic ellipsometry and attenuated total reflection analyses of Al2O3/HfO2 nanolaminates

The microstructure of thin HfO2–Al2O3 nanolaminate high κ dielectric stacks grown by atomic vapor deposition has been studied by attenuated total reflection spectroscopy (ATR) and 8eV spectroscopic ellipsometry (SE). The presence of Al2O3 below HfO2 prevents the crystallisation of HfO2 if an appropriate thickness is used, which depends on the HfO2 thickness. A thicker Al2O3 is required for thicker HfO2 layers. If crystallisation does occur, we show that the HfO2 signature in both ATR and 8eV SE spectra allows the detection of monoclinic crystallites embedded in an amorphous phase.