Ikarashi N, Ishida K
Microelectronics Research Laboratories, NEC Corporation, Tsukuba, Japan.
Microsc Res Tech. 1998 Feb 1;40(3):187-205. doi: 10.1002/(SICI)1097-0029(19980201)40:3<187::AID-JEMT3>3.0.CO;2-S.
We have established a (110) cross-sectional high-resolution transmission electron microscopy (HREM) method to observe atomic structures of semiconductor hetero-interfaces. We show theoretically that the semiconductors in a hetero-structure exhibit strong contrast for an EM specimen thickness near their extinction distances, allowing atomic-scale observations of the interfacial structures between them. Furthermore, to obtain a clear HREM image, an EM specimen preparation technique is developed in which chemical etching is used to remove ion milling artifacts. This HREM method allows edge-on imaging of interfaces formed along the (110) direction; observations of atomic steps at AlAs/GaAs interfaces and a chemically ordered structure at Si/Ge interfaces are demonstrated.
我们建立了一种（110）截面高分辨率透射电子显微镜（HREM）方法来观察半导体异质界面的原子结构。我们从理论上表明，异质结构中的半导体在接近其消光距离的电子显微镜（EM）样品厚度下表现出强烈的对比度，从而能够对它们之间的界面结构进行原子尺度的观察。此外，为了获得清晰的高分辨率透射电子显微镜图像，开发了一种电子显微镜样品制备技术，其中使用化学蚀刻来去除离子铣削伪像。这种高分辨率透射电子显微镜方法允许对沿（110）方向形成的界面进行侧视成像；展示了对AlAs/GaAs界面处原子台阶和Si/Ge界面处化学有序结构的观察。
