January 21, 2005 – Carl Zeiss SMT has announced it has achieved a record image resolution of 0.8 angstrom (0.08nm) during qualification of its latest generation ultra-high-resolution transmission electron microscope (UHRTEM).
The milestone was achieved using a newly developed 200 kV field-emission UHRTEM equipped with electron optical components for aberration correction, electron beam monochromatization, and energy filtered imaging, partly co-developed with CEOS GmbH, Heidelberg.
By unique and proprietary integration of these advanced components into a new UHRTEM platform, image resolution of even down to 0.7 angstrom was demonstrated for certain image directions, which nearly equals the theoretically achievable resolution limit. The TEM instrument is specifically designed for sub-angstrom characterization of advanced materials and device structures, e.g. for atomic scale analysis of transistor gate areas, and will be made available to demanding customers in cutting-edge nanotechnology research and development.
For demonstration of the achieved image resolution, Young’s fringes patterns (as exemplified in the picture) have been generated from micrographs recorded at 800,000 times image magnification and image acquisition times of one second.
The energy spread of the field emission source was reduced by the monochromator to 0.2 eV and a residual spherical aberration of the objective lens (Cs value) of approximately -3 µm was obtained using the integrated aberration corrector from CEOS GmbH. An amorphous Tantalum thin film was used as specimen.
Four ring insets, calibrated by gold lattice reflections, indicate the 1.0, 0.9, 0.8 and 0.7 angstrom resolution limits (from inside to outside). For all image directions, the fringe contrast clearly extends to the 0.8 angstrom ring and even extends to the 0.7 angstrom ring for certain image directions.