Abstract
According to “The Principle of Reciprocity”, except for High-angle annular dark field image (HAADF) there is another kind of Z-contrast image, ”Hollow Cone Dark Filed (HCDF) image”. In this thesis, the technique of developing Z-contrast hollow cone dark field (HCDF) images by recording a series of high-angle centered dark field (CDF) images in JEOL 2000FXII TEM will be demonstrated. And two applications of the HCDF method, the VLSI device sample and the Al-Cu alloy sample, will be given. And the well known Z-contrast STEM-HAADF images were also taken for comparison with the HCDF images. The results show that the diffraction contrast can not be eliminated entirely in both HCDF and HADF images. Increasing the collection (cone) angle of HCDF images can effectively suppress the influences of the diffraction contrast. Also the HAADF image with a larger collection range suffers less influence of the strain field on intensities than the HCDF image. The HAADF imaging is higher Z-dependent and sharper in edges than HCDF imaging. However, HCDF imaging still performs satisfied results for medium resolution applications.