[Show abstract][Hide abstract] ABSTRACT: We have successfully developed a spherical aberration (Cs)-corrected electron microscope for probe- and image-forming systems using hexapole correctors. The performance of the microscope has been evaluated experimentally. The point resolution attained using the image-forming Cs-corrector is better than 0.12 nm. For scanning transmission electron microscopy, the Ronchigram flat area was >40 mrad in half-angle using the probe-forming Cs-corrector.
No preview · Article · May 2005 · Journal of Electron Microscopy
[Show abstract][Hide abstract] ABSTRACT: A spherical aberration (Cs)-corrected 200 kV TEM was newly developed. The column of the microscope was extended by 25 cm and the inner yoke of the objective lens was modified to insert some parts of the corrector elements. The corrector has two hexapole elements that play a main role in Cs correction and they are placed at a position equivalent to the coma-free point of the objective lens by using two transfer doublet lenses. The Cs correction was successfully carried out by means of the third-order aberration that was generated in the two extended hexapoles. The Cs can be corrected to the desired value and also can be overcompensated in order to produce a negative Cs, as with the corrected Cs of -23 microm shown in this work. The optical system of the corrector does not produce second- and fourth-order aberrations, and can correct residual aberrations up to the third order. All of the corrector elements are computer-controlled and the third-order aberrations are quite stable after they are properly corrected. The resolution of 0.135 nm was experimentally confirmed by the Young's fringe method. Image simulations of a silicon  single crystal were made with various Cs and defocus values to demonstrate the effectiveness of arbitral control of Cs.
No preview · Article · Feb 2003 · Journal of Electron Microscopy
[Show abstract][Hide abstract] ABSTRACT: Mirror symmetry, no symmetry and glide symmetry of crystals are displayed using interference (lattice) fringes appearing in overlapping disks of convergent-beam electron diffraction (CBED) patterns. The lattice fringes with a spacing of 2.7 Å of the 200 reflection of FeS2 have been observed in coherent CBED patterns with use of a JEM2010F electron microscope equipped with a field-emission gun. Two-dimensional interference fringes are shown in three overlapping disks taken from FeS2 at  electron incidence. It is demonstrated that such lattice fringes can be obtained even by an LaB6 electron source when using imaging plates.
[Show abstract][Hide abstract] ABSTRACT: The interference fringes with a lattice spacing of 1.92 Å for the 220 reflection of Si have been observed in convergent-beam electron diffraction patterns using a JEM 2010F electron microscope equipped with a field-emission gun. The fringes observed in the present study have the smallest lattice spacing among the fringes reported to date.