Optimizing the recognition of surface crystallography

0431336 - ÚPT 2015 CZ eng A - Abstrakt
Frank, Luděk - Müllerová, Ilona
Optimizing the recognition of surface crystallography.
9th International Conference on Charged Particle Optics. Book of Abstracts. Brno: Institute of Scientific Instruments AS CR, v. v. i, 2014. s. 88. ISBN 978-80-87441-11-4.
[International Conference on Charged Parrticle Optics /9./. 31.08.2014-05.09.2014, Brno]
Grant CEP: GA TA ČR TE01020118
Institucionální podpora: RVO:68081731
Klíčová slova: SEM * crystallography
Kód oboru RIV: JA - Elektronika a optoelektronika, elektrotechnika

Acquisition of surface crystallographic information represents a task of continually increasing importance for analytical instrumentation. In particular, the scanning electron microscopy is capable of serving this purpose at high to medium electron energies by means of the diffraction-based EBSD method, as well as at low and very low energies in the backscattered electron (BSE) mode. What is traditionally neglected is utilization of information contained in the overall angular distribution of non-diffracted BSE. We have equipped our ultrahigh vacuum scanning low energy electron microscope with a scintillatorbased detector of BSE, freely movable above the sample in a plane containing the optical axis, in order to acquire BSE from a particular interval of the polar angles of emission (scintillator size establishes the FWHM to between 9 and 19°). The sample was a polycrystalline 98Cu2Sn alloy cleaned by means of repeated Ar ion beam bombardment and annealing. Atomical cleanliness was checked by Auger spectroscopy. Grain contrast was measured for selected couples of grains. Preliminary results show the grain contrast generally increasing with the polar angle and achieving a maximum near 80°, and usually increasing with the decreasing landing energy of electrons. In practice, BSE polar angles approaching 90° can be acquired when immersing the sample in an electric field like in a cathode lens.
Trvalý link: http://hdl.handle.net/11104/0236397