=================================================================================
Nowadays, more and more aberration corrected electron microscopes (EMs) are installed in scientific laboratories and industrial companies. However, not all the aberration corrected EMs are fully functioning or applicable to the organizations. On the one hand, aberration correction works only if the information limit of the microscope is smaller than the resolution limit defined by spherical aberration (Cs) or chromatic aberration (Cc) . Therefore, it is important that all the incoherent disturbances affecting the information limit are eliminated or sufficiently suppressed [1]. For instance, up to now only the corrections have been achieved successfully for the low-voltage SEM [2], the 200 kV TEM [1,3] and the 100 kV or higher STEM [4]. On the other hand, some aberration corrected EMs are not really applicable for some organizations, partially from the economic point of view. For instance, some organization would like to buy a conventional TEM/STEM instead of an aberration corrected SEM because the TEMs in combination with STEM can be much cheaper than an aberration corrected SEM and the TEM/STEM operation can be much simpler. Moreover, to have lattice fringes the “depth resolution” in SEMs has to be worse in order to enhance the signals from secondary electrons or backscattering electrons.
[1] M. Haider, H. Rose, S. Uhlemann, B. Kabius, K. Urban,
J. Electron Microsc. 47 (1998) 395.
[2] J. Zach, M. Haider, Nucl. Instrum. Methods A 363 (1995)
316.
[3] M. Haider, H. Rose, S. Uhlemann, E. Schwan, B. Kabius,
K. Urban, Ultramicroscopy 75 (1998) 52.
[4] O.L. Krivanek, N. Dellby, A.R. Lupini, Ultramicroscopy
78 (1999) 1.
|
