Simulation on Plasma Discharge and Transport in Large and Complex Geometric Space

Abstract The plasma discharge and transport properties in the vacuum systems is critical for film deposition controlling. However, industrial-scale vacuum systems usually exhibit large and complex geometries, leading to boundary distortion and convergence difficulty in the conventional simulation techniques. In this work, a PIC/MCC model with FEM solver for non-uniform grids is established to precisely construct a large simulation domain with complex boundaries using the fluid model, and tracks the charged particle movements in non-uniform electromagnetic fields by the PIC/MCC method. The discharge process in a large cylindrical vacuum chamber shows the obvious interaction between the spatial electromagnetic field and plasma. The distribution of deposited ions is consistent with the potential gradient of the sheath. Besides, the ion deposition proportion is increased by more than 3 times and the average ion energy is increased by over 45.0 eV compared with the constant potential, indicating that the background electric field plays a significant role. When the spatial potential is steady, the plasma leads to stable accumulation with the peak density of 1015 m-3 achieving convergence at 0.3 μs, thus demonstrating the excellent operation speed and convergence compared to the individual fluid model and PIC/MCC method. The density of the computational grids modified further according to the Debye length reveals a significantly improved computational performance with the convergence process compressed into 0.26 μs and the total runtime reduced by 40%.