Applications of Scanning Transmission Electron Microscopy (STEM) in the New Generation of High-K Gate Dielectrics

Scanning transmission electron microscopy (STEM) Z-contrast image has some advantages such as high image resolution (directly revealing the real positions of atoms in crystal), high compositional sensitivity and directly interpretable images, it becomes a powerful tool for investigating the microstructure of materials at atomic scale. In this review, the formation mechanisms, methods and features of the Z-contrast STEM images are introduced, and its applications in the new generation of high-k gate dielectrics (e.g., Hf-based metals oxides, rare-earth oxides and epitaxial perovskite oxides) are also reviewed. After aberration-correction the spatial resolution of the Z-contrast STEM images is as high as the sub-A level, this technique is invaluable for characterizing the interfacial structures between high-K gate dielectrics and semiconductors. The related results are also introduced.