Both columns consist of two lenses (condenser and objective, namely) to focus the beam on sample, apertures to define beam diameters and beam current, deflections plates, stigmators, blanker etc. How do you separate the two column designs?
AFIB setup is a scientific instrument that resembles a scanning electron microscope ( SEM ). However, while the SEM uses a focused beam of electrons to image the sample in the chamber, the FIB setup uses a focused beam of ions instead. Unlike an electron microscope, FIB is inherently destructive to the specimen. .
Dear Dr. Omer Sise,
the structure of FIB is similar to that of SEM. The major difference between FIB and SEM is the usage of a gallium ion (Ga+) beam instead electron beam. Therefore the ion energy for bombardment/collisioni s more higher than that of the electron energy. Direct material removal can be realized accordingly. A vacuum of about 1x10-7 mabar is mantained inside the column. This electric field causes the emission of positively charged ions from a liquid gallium cone, which is formed on apex of a tungsten needle. After a first refinement through the spray aperture, the ion beami s condensed in the first electrostatuc lens. The upper octopole then adjust the beam stigmatism.. Using the variable sperture mechanism, the beam current can be varied over four decades, allowing a fine beam for both high-resolutin imaging on sensitive samples and a heavy beam for fast and rough milling. Typically, total seven values of the beam current can be selected for users in the commercial FIB machines. Blanking of the beami s accomplished by the blanking deflector and aperture, while the lower octopole is used foir raster scanning the beam over the sample. In the second electrostatic lens, the beami s focused to a fine spot, enabling a best resolution in the scale sub 10 nm. The multi-channel plate is used to collect secondary particles for imaging.
For more details, please see the source:
-Subwavelength Optics – Theory and Technology (Vol. 1)
By Yongqi Fu – Bentham Science, UAE (2009)
ISBN: 978-1-60805-050-5
Best regards, Pierluigi Traverso
A FIB setup is a scientific instrument that resembles a scanning electron microscope (SEM). However, while the SEM uses a focused beam of electrons to image the sample in the chamber, a FIB setup uses a focused beam of ions instead. Unlike an electron microscope, FIB is inherently destructive to the specimen.
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