Development of high‐resolution field emission scanning electron microscopy with multifunctions for chargeless observation of nonconducting surface

Abstract

AbstractWe have developed a fully digital field emission scanning electron microscope (FE‐SEM) with multifunctions to compensate the charging up of nonconducting surfaces. High‐voltage observation, minimum electron dose, variable scanning speed, averaging, integration, tuning of surface potential, and cyclotron movements of secondary electrons have been achieved. This FE‐SEM was successfully applied to observe resist, diatomaceous earth, aluminum oxide, and zeolite surfaces. The accelerating voltage is changeable in a range from 0.5 to 30 kV, and the probe current on the sample can be varied from 2×10‐9 to l×10‐13A to supply optimum electron dose. By using a snorkel‐ type, strongly excited objective lens (OL) immersing the samples in the magnetic field, the secondary electrons are extracted from the sample. For guiding electrons into the built‐in lens‐type secondary electron detector (SED), newly developed accelerating and retarding electrodes are installed in the OL to tune the surface potential. Furthermore, this FE‐SEM can select 10 scan speeds, and the averaging and integration of secondary electron image signals are possible under every selected scan speed.