Electrostatic correction of the chromatic and of the spherical aberration of charged-particle lenses (part I).
A feasible electrostatic corrector (ECO) is outlined and the principle of the electrostatic correction is elucidated by means of a light-optical analogue. The ECO compensates for the chromatic and the spherical aberration of charged-particle lenses and reduces the resolution limit of a special LVSEM (low-voltage scanning electron microscope) from 6 nm to 1.4 nm. The geometry of the electrodes of the corrector is optimized with respect to the chromatic correction, the maximum strength of the electric field, and the residual higher-order aberrations which limit the resolution. In addition the stability criteria of the electric power supplies are discussed in detail.
Weissbäcker
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Institute of Applied Physics, Darmstadt, Germany. chris@marvin.iap.physik.tu-darmstadt.de
Rose
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