Post‐Deposition Annealing Analysis for $HfO2$ Thin Films Using GIXRR/GIXRD

High‐k materials, such as $HfO2,$ $Al2O3,$ and many others, have been employed to replace the $SiO2$ insulator in the gate dielectric device in order to offer significant gate leakage reduction. In this study, the physical properties of hafnium dioxide $(HfO2)$ thin films were analyzed and characterized in the cases of ‘as‐deposited’ and ‘post‐deposition annealing’ (PDA). Ultra‐thin hafnium dioxide films of thickness 2.5, 5 and 10 nm were deposited on Si (100) substrates using atomic layer deposition (ALD) at temperature of 300° C. After deposition, the films were annealed using furnace in Ar ambient for 10 minutes at 450° C, 550° C, 650° C and 750° C. The thickness, density, roughness and the crystalline evolution of the $HfO2$ films were investigated by Grazing Incidence X‐Ray Reflectometry (GIXRR) and Grazing Incidence X‐Ray Diffraction (GIXRD) for both as‐deposited and post‐annealing conditions. Transmission Electron Microscope (TEM) was used to provide image verification of the two‐layer model applied in XRR fitting analysis. Furthermore, the grain sizes were evaluated by X‐ray diffraction peak‐broadening (full width at half maximum, FWHM) calculation according to the Scherrer method. The experimental results showed that the annealing temperatures had significant impact on the thickness, density and roughness of the $HfO2$ and $SiO2$ layers. In addition, the experimental results demonstrated the grain sizes depend on not only the thickness of the film, but also the annealing temperatures in the crystallization process.