Optimization of Beam Parameters to Obtain High Quality Electron Microscopic Image

Obtaining an image of a three-dimensional (3D) object is remarkably easy with a field emission scanning electron microscope (FESEM). To obtain all the information the SEM can provide, however requires an understanding of the major modes of microscopy and the electron beam parameters that affect them. The amount of electron current in the final probe determines the intensity of the secondary electron signal. The smaller the electron probe, the lower is the probe current available hence the visibility of the features on the image obtained will be poorer. The accelerating voltage (kilovolts) of the beam determines how accurate the image will be in representing the actual surface of the specimen. This paper will discuss high-to-low-voltage mode of imaging with Carl Zeiss GeminiSEM 500 at different aperture size. It is not easy to determine the right accelerating voltage for a sample; high voltage seems good for some sample but might destroy the delicate parts of some specimen. The operator must know how to control these beam parameters to achieve optimum results in each microscopy mode. In this paper we will describe the optimization of electron beam parameters for examples aperture size and accelerating voltage for different type of samples to obtain high quality microscopic image. (author)