A calculation approach for current density distribution evolution of secondary electrons using differential algebra...

Area of Science:

• Physics
• Electron Optics
• Materials Science

Background:

• Secondary electron (SE) beam current density distribution (CDD) evolution is crucial for understanding electron optics.
• Accurate modeling of SE beam CDD is essential for optimizing detector systems in electron microscopy.

Purpose of the Study:

• To present a novel differential algebra (DA) method for calculating the current density distribution (CDD) evolution of secondary electron (SE) beams.
• To validate the proposed method through simulations and experimental observations in a scanning electron microscope (SEM) setup.

Main Methods:

• The proposed method divides the SE beam into beamlets and traces reference trajectories using the DA method.
• Transfer properties of each beamlet are calculated, enabling derivation of the current density function considering initial distributions and emission source size.
• The total CDD evolution is obtained by superposing the CDDs of individual beamlets.

Main Results:

• The differential algebra method successfully calculates SE beam CDD evolution.
• Simulations and experimental results for a SEM SE detection system show good agreement, validating the method.
• The approach provides a tool for analyzing and optimizing SE detection systems.

Conclusions:

• The proposed DA-based method offers an accurate and efficient way to calculate SE beam CDD evolution.
• This method has significant potential for optimizing SE detection systems and enhancing collection efficiency in SEMs.
• The validated approach bridges simulation and experimental data for secondary electron imaging.