扫描透射电子显微镜(STEM)在新一代高K栅介质材料的应用

扫描透射电子显微镜(STEM)原子序数衬度像(Z-衬度像)具有分辨率高(可直接“观察”到晶体中原子的真实位置)、对化学组成敏感以及图像直观易解释等优点, 成为原子尺度研究材料微结构的强有力工具。本文介绍了STEM Z-衬度像成像原理、方法及技术特点, 并结合具体的高K栅介质材料 (如铪基金属氧化物、稀土金属氧化物和钙钛矿结构外延氧化物薄膜)对STEM在新一代高K栅介质材料研究中的应用进行了评述。 目前球差校正STEM Z-衬度的像空间分辨率已达亚埃级, 该技术在高K柵介质与半导体之间的界面微结构表征方面具有十分重要的应用。对此, 本文亦进行了介绍。

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-Å level, this technique is invaluable for characterizing the interfacial structures between high-K gate dielectrics and semiconductors. The related results are also introduced.