(110) HREM of interfacial structures in semiconductor hetero-structures.
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.
Ikarashi
N
N
Microelectronics Research Laboratories, NEC Corporation, Tsukuba, Japan.
Ishida
K
K
D007089:Image Enhancement; D008432:Mathematical Computing; D008854:Microscopy, Electron / Q000379:methods*; D015394:Molecular Structure; D012666:Semiconductors