High-Powered Electron Beam Properties in PVD using the Kinetic Simulation Tool PICLas and Experimental Validation

This study focuses on the electron beam propagation used in physical vapor deposition, specifically examining the self-focusing effect induced by ionization processes and the resulting beam diameter before entering the coating chamber. Using the open-source plasma simulation framework PICLas, the Particle in Cell (PIC) method was coupled with the Monte Carlo Collision (MCC) method. This enabled the simulation to account for the self-fields of charged species, a super-imposed magnetic field and the ionization processes due to the presence of a neutral background gas. The results demonstrate the self-focusing effect in the presence of background ionization. To address the different time scales of electron and ion movement, we implemented a species-specific time step, accelerating convergence while capturing the electron beam dynamics. The simulated electron beam widths were compared with measurements, where the burn-in diameter in a metal mesh indicated the width of the beam. Our comparison shows good agreement between the simulated and measured electron beam widths along the beam generator. This work underscores the importance of considering ionization-induced focusing effects when designing and optimizing electron beam generators.