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Guaranteed image resolution on test sample
| | The SUPRA™ has been built around the unique GEMINI® lens design which has many advantages over classical lens designs:
The most important feature is the decreasing aberrations with decreasing beam energy. Therefore it delivers superb resolution down to 100 eV (or better) and at 30 kV its resolving power is unsurpassed.
The high-angled GEMINI® objective lens body allows 50° of large specimens (e.g. 6“ wafers) at a working distance as low as 6 mm. The analytical working distance for EDS analysis with a take off angle of 35° is only 8.5 mm - suitable for high resolution imaging.
The GEMINI® objective lens consists of a high performance magnetic lens with an inserted electrostatic lens. The GEMINI® concept has overcome the problem with classical objective lens designs which immerses the specimen in their magnetic field prohibiting imaging. The GEMINI® magnetic lens is shaped to minimize the magnetic field at the specimen. Therefore high resolution imaging of dia-, para-, or ferromagnetic samples is possible with very short working distances.
The magnetic/electrostatic lens combination is equivalent to an optical lens triplet which increases the incident beam aperture angle at the specimen and hence improves resolution. The increase of the optimum beam aperture angle also provides a larger electron probe current and hence generates a superior signal to noise ratio of the image. The lens control system is with integrated condenser control will always select the optimum beam aperture for any working distance and / or selected energy. Consequently the SUPRA™ delivers excellent image contrast even at the resolution limit.
A single-stage beam scanning system is integrated in the GEMINI® lens, just in front of the electrostatic lens gap. Therefore the transverse chromatic and other scanning aberrations have been minimized. The instrument operates without distortion at TV-scanning speed from the lowest (12x) to the highest (900,000x) magnification. In particular, no switchover is required between a low magnification mode and a high resolution mode.
The GEMINI® objective lens provides outstanding resolution and image quality, especially at low beam voltages without any compromise in operational convenience. |