A comparison of conventional Everhart-Thornley style and in-lens secondary electron detectors: a further variable in scanning electron microscopy.

The secondary electron (SE) imaging of several samples across a range of scanning electron microscopes (SEM) and SE detectors under matched operating conditions has generated a highly variable image data set. Using microanalytical conditions (10-15 kV), images from in-column SE detectors reveal the presence of surface films and contaminants that are invisible to conventional Everhart-Thornley SE detectors under the same conditions. Data from studying the effects of working distance, the image resolution derived through contrast transfer function analysis and electrostatic mirror imaging of the SE detectors in operation combine with other studies to suggest that the classically defined SE1 component can be separated from other SE components. SE images obtained by tailored mechanical design and energy-filtering will provide SE images with probe-sized resolution and dominated by surface detail currently only seen in low-voltage SEM, potentially even from thermionic-sourced columns.