ISM 2022 (Microscopy)


Asia Matatyaho-Ya'akobi Yeshayahu Talmon
The Department of Chemical Engineering and The Russell Berrie Nanotechnology Institute (RBNI), Technion-Israel Institute of Technology, Haifa, Israel

Scanning electron microscopy (SEM) is one of the most widely used electron microscopy techniques in science and engineering. Although the SEM was originally intended for operation at low beam acceleration voltages (BAV), it was only possible to operate at low beam energies decades after the first commercial SEM was available. Hence, most of the pioneering studies of the electron-specimen interaction physics have been conducted at BAV above 5 kV. Currently, low voltage imaging has become more prevalent due to the more practical field emission guns (FEGs), which have high brightness even at low acceleration voltage. That and the improved optics, vacuum, and detectors in modern SEMs, allow the acquisition of high-resolution information.

The high-resolution modern SEMs are flexible instruments allowing operation over a wide range of parameters. Optimizing the operation parameters is essential for obtaining high-quality micrographs and avoiding imaging artifacts. One of the major and common SEM imaging artifacts is specimen charging. With low voltage imaging, it is now evident that it is possible to avoid charging artifacts with a proper selection of operation parameters, even when imaging non-conducting specimens without the application of conductive coating. Moreover, the operating parameters could be adjusted to enhance the micrograph contrast.

In this work, we investigate the effect of SEM operation parameters on contrast formation when imaging various materials. The materials in this study have different combinations of conductive and non-conductive systems. We study the change of the contrast in the final micrograph when data are acquired at different working distances, at different acceleration voltages, and with different detectors. We show the importance of selecting adequate acquisition parameters when using SEM, to obtain an optimal micrograph with enhanced contrast.