Berlin 2015 – wissenschaftliches Programm

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MI: Fachverband Mikrosonden

MI 3: Analytical Scanning Electron Microscopy

MI 3.3: Vortrag

Montag, 16. März 2015, 16:00–16:15, EMH 225

A Mirror-Corrected Scanning Electron Microscope — •Peter Gnauck and Markus Boese — Carl Zeiss Microscopy, Oberkochen, Germany

In materials science and biological research the Scanning Electron Microscope (SEM) has a long tradition. In recent years the interest in the imaging of sensitive samples and the material contrast at a high lateral resolution has grown. Lowering the primary electron energy helps to reduce the sample damage. On the other hand the interaction volume is decreased, thus increasing the lateral information from the backscattered electron signal.

However, the low primary electron energy is extremely demanding to the electron optics, if not too much of the lateral resolution should be lost due to the increased wavelength of the electrons. In a suitable instrument typically the spherical and the axial chromatic aberration have to be corrected. Additionally, innovative detector schemes can provide enhanced analytic capabilities and can avoid limitations by signal noise and residual instrumental instabilities.

We will discuss a mirror-corrected SEM, offering high-resolution analytics with efficient productivity to visualize even the most sensitive materials by use of electrons with energies far below 1keV. At these energies the resolution of conventional instruments is very poor, but compensating for the primary aberrations of the objective lens can overcome this obstacle. The aberration correction by means of an electron mirror significantly increases the resolution especially for low energies; this has been proven in a unique spectro-microscope.