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Optical techniques that use a spectral range of photon energies larger than the band gap are very sensitive for structural characterization of semiconductor nanocrystals. Techniques that can measure the change of polarization during reflection from bulk or thin film samples reveal high sensitivity for both the layer thickness and the refractive index. From one spectroscopic ellipsometric measurement performed in a range of 0.7-6.5 eV within 1 s using a standard multi-channel ellipsometer not only the thickness and the dielectric function of the film, but a range of derived material properties like the crystallinity or the size and volume fraction of nanocrystals can be determined indirectly. The quality of the measurement is not any more a question of instrumentation, but rather a question of interpretation and proper modeling. In this paper we summarize what parameters can be determined, and we present a method for the reliable fitting of numerous parameters.

Nanometre thin high-k hafnium oxide (HfO2) layers combined with a sub-nm SiO2 layers or Hf silicate have become Si compatible gate dielectrics. Medium energy ion scattering (MEIS) analysis has been applied to a range of such MOCVD grown HfO2/SiO2 and HfSiOx(60%Hf)/SiO2 gate oxide films of thickness between 1 and 2 nm on top of Si(100), before and after decoupled plasma nitridation (DPN). MEIS in combination with energy spectrum simulation provides quantitative layer information with sub-nm resolution on these layer structures and their atomic composition that is in excellent agreement with a) the as grown layer parameters and b) results obtained from techniques, such as SE, XPS, XRF and XTEM. MEIS analysis of a metal gate, high-k TiN/Al2O3/HfO2/SiO2/Si stack shows the interdiffusion, after thermal treatment, of Hf and Al from the caplayer, which was inserted to modify the metal gate work function.

The properties of Ge-HfO2and Ge-ZrO2films were studied versus Ge content and annealing temperature by means of Raman scattering, FTIR and X-ray diffraction methods. Ge-HfO2films with [Ge]<5 at.% were polycrystalline, whereas higher Ge content stabilized amorphous structure that was stable for T<600°C. The T increase caused the formation of Ge clusters and tetragonal HfO2phase. This latter appeared at T=600-670°C, while the Ge clusters crystallized at T=700-800°C. Unlike to Ge-rich HfO2films, as-deposited Ge-ZrO2films and those annealed at T≤600°C were amorphous. In these films, formation of Ge clusters and their crystallization occurred at T=640-700°C depending on Ge content, whereas ZrO2phase crystalized at T=680-700°C that allowed to form Ge nanocrystals in amorphous matrix at T=640-680°C. For T>800°C, the films showed appearance of monoclinic HfO2or ZrO2phases that was explained by the Ge content decrease via volatile GeO formation. Obtained results supported theoretical prediction of the stability of tetragonal phases in these oxides via Ge doping. However, our results showed also some difference in the phase separation process of Ge-rich HfO2and Ge-rich ZrO2upon thermal treatment.