Strain relaxation near high-k/Si interface by post-deposition annealing

Comparing the rocking curves before annealing the sample with those of the annealed sample, it is found that an interfacial layer with a density of 3 g/cm3 grows at the interface between the HfO2 layer and the substrate during post-deposition annealing. The wavelength dependency of the integrated intensities of the rocking curve for the as-deposited sample fluctuated with the observation position. This fluctuation was suppressed by annealing. From these results we concluded that the strain introduced into the substrate becomes homogeneous by annealing. Moreover, a quantitative estimation of the strain by curve fitting reveals the existence of compressive strain under the HfO2 layer.