Simulation and Analysis of PECVD Process for Silicon Nitride Deposition Using CFD: Impact of Pressure on Deposition Uniformity

This study presents a computational fluid dynamics (CFD)-based simulation of the plasma-enhanced chemical vapor deposition (PECVD) process utilizing COMSOL Multiphysics. Specifically, the research focuses on the deposition of silicon nitride (SiNx) on silicon wafers, where this layer functions as an anti-reflective coating (ARC) to enhance light absorption. Regardless of the solar technology in question such as passivated emitter and rear contact (PERC), tunnel oxide passivated contact (TOPCon), hetero-junction technology (HJT), or tandem, understanding the deposition of ARC is crucial. This work simulates the multi-physics involved in PECVD process, encompassing fluid flow, plasma reactions, gas-phase reactions, and surface reactions. In this work we successfully demonstrated the modelling of the complex PECVD process capturing various physics like fluid flow, plasma physics, heavy species transports, and plasma, gas-phase, as well as surface reactions, and further validated it experimentally. The model was then used for various parametric studies i.e., effect of input parameters like pressure and temperature on the key output parameter i.e., deposition rate. This research not only demonstrates the capability of simulating intricate solar manufacturing processes like PECVD but also lays the groundwork for future simulation-based optimization of such processes and creating digital-twins as a part of Industry 4.0. This study represents the first documented investigation in the literature to report electron density distribution and transient thin film growth dynamics on silicon wafers within a tubular PECVD chamber.