Electron-Beam Reflection Investigation Concerning Charged Disc and Multipole Approximations

The influence of the surface sample potential on the head-incident electron beam in the scanning electron microscope has been studied in terms of the mirror effect.The multipole and charged disc models have been used to approximate the sample potential.The energy conservation law is used to assist set up the equation of motion for the incident electron.The point of reflection of the electrons along the length between the sample surface and the column diaphragm is then determined by solving the equation.In fact, the beam and surface potential characteristics mostly determine the reflection point's value.In light of the variations between the two models that were utilized, the reflection behavior was examined in terms of these characteristics.The outcomes have demonstrated that, when it comes to simulating the surface potential, each model has both advantages and disadvantages.In reality, the two models exhibit comparable results over a broad range of distances between the sample surface and the column diaphragm when the common parameters are placed in parallel.However, the variance between them occurs in a very short distance that almost does not exceed 13% approximately.Nevertheless, because of its own mathematical nature, the multipole model is best appropriate to estimate the surface potential of highly concentrated trapped charges.Meanwhile, the charged disc model is suitable for approximating the surface potential for low concentrated trapped charges.