|
|
Electron optical properties of a new low-energy scanning electron microscope with beam separator
Radlička, Tomáš ; Kolařík, V. ; Oral, Martin
The low energy scanning electron microscope (SEM) which is currently at the Institute of\nScientific Instruments, suffers from low resolution and suboptimal detections systems. In the cathode lens regime, signal electrons are accelerated by the electric field between the sample and the objective lens, getting collimated. Those with low emission angles get through the bore in the BSE detector into the objective lens and cannot be detected by the available detectors now. The information about the sample provided by these electrons is lost, which limits our microscopy methods.\nThese two limitations are to be overcome with a new low-energy SEM, which was developed\nat Delong Instruments. It consists of a field emission gun with the energy width of 0.8 eV, a magnetic condenser lens, and an electrostatic triode objective lens. The acceleration voltage is 5 kV. The sample stage can be biased at up to -5 kV to provide low landing energy without strong decrease of the resolution – the effect of the cathode lens. A beam separator is placed in front of the deflection system for the detection of the signal electrons that get to the column. In a combination with standard detectors and cathode lens, it allows detecting all\nkinds of signal electrons.
|
guest ::
