Three-dimensional simulation research on plasma uniformity engineering: diamond film uniformity regulation based on resonant cavity structural resonance design

The polycrystalline diamond films have attracted considerable attention in the field of thermal management in high-frequency, high-power devices. However, non-uniform plasma distribution during the film fabrication process results in significant variations in film performance, which poses a substantial challenge to their practical application. To this end, the finite element method was employed to conduct a 3D simulation of non-uniform plasma distribution induced by structural anharmonicity in the MPCVD reactor. Research findings indicate that when the resonant cavity experiences geometric misalignments such as deflection or offset, leading to structural anharmonicity, the high power density region of the plasma will shift in a direction opposite to the change in structural resonance. The anharmonicity of the resonant cavity structure, which leads to a non-uniform plasma distribution, can be effectively compensated for by adjusting the structural resonant characteristic. For instance, when the resonant cavity antenna structure is deflected by 2°, the plasma will demonstrate a significant shift. By translating the substrate along the direction of this plasma shift by 3 millimeters, it can be restored to its central axis position within the resonant cavity. This investigation provides a novel theoretical foundation and technical pathway for the regulation of plasma spatial uniformity. • Adjusting the structural anharmonicity of the resonant cavity induces changes in both diamond growth status and plasma distribution. • When the resonant cavity structure experiences structural anharmonicity, the plasma will shift in a direction opposite to the change in structural resonance. • The anharmonicity of the resonant cavity structure, which leads to a non-uniform plasma distribution, can be effectively compensated for by adjusting the structural resonant.