High-resolution (HR) SEM
By high-resolution (HR) SEM, we denote imaging of the sample with high accuracy, in order to faithfully represent the surface morphology. Instrumentally, there are two typical requirements. Firstly, a field emission gun and suitable electron optics that converge the beam in to a narrow (e.g. 1 nm diameter) electron probe with high brightness. Secondly, a SE detector that eliminates any possible signal from backscattered electrons, since their large interaction volume degrades image resolution (see BE imaging).
In CIME, the Zeiss Merlin enables high resolution mode imaging. In HR mode, the temperature of the Schottky emitter and the extraction voltage are reduced. This leads to a reduction of the energy spread of the primary electrons. It is especially useful at low kV to reduce chromatic error and achieve a better resolution.