Development of Scanning Confocal Electron Microscopy
Abstract: Confocal imaging in scanning transmission electron microscopy (STEM) is a new technique for performing depth sectioning of specimens in a transmission electron microscope. This is called scanning confocal electron microscopy (SCEM). In the present work, we have developed two base technologies, 3D specimen scanning system and annular dark field (ADF) confocal imaging optics, to realize SCEM practically, and performed depth sectioning with depth resolution less than 100nm using a conventional transmission electron microscope JEM-2100F. And, it was demonstrated that 3D reconstruction could be obtained by SCEM for the first time. Furthermore, ADF-SCEM using a JEM-2200MCO machine equipped with aberration correctors in its probe-forming and imaging lenses was performed, and about 20nm in depth resolution was achieved. This paper aims at introducing a principle and outline of ADF-SCEM and showing some experimental results.
Key words: Scanning Confocal Electron Microscopy (SCEM), annular dark field (ADF), depth resolution, depth sectioning