Effect of substrate stage height on single crystal diamond growth in MPCVD reactor: Simulated and experimental perspective

The preparation of high-quality single crystal diamonds is crucial for achieving efficient, high-performance electronic devices, optical systems, and power devices. Recently, simulation of the diamond MPCVD growth chamber has become a hot research topic, as it can guide the growth process and reduce costs. Among them, the substrate stage structure has a great influence on the physical fields of the chamber. Some studies have discussed the influence of the substrate stage height on the chamber in a H₂ system, ignoring the influence of CH₄ on the plasma and radical distribution. Here, a self-consistent model including electromagnetic field, plasma, and fluid heat transfer is developed to systematically simulate the plasma behavior in the CH₄-H₂ reaction chamber for MPCVD diamond growth. The study focuses on analyzing the effect of substrate stage height on plasma distribution within the chamber, including the distribution of the electric field, electron density, temperature field, and radical concentrations (CH₃, H). In addition, the accuracy of the simulation was verified by In-situ optical emission spectroscopy (OES) and experimental results. This investigation aims to clarify the relationship between plasma dynamics and diamond growth reactions, thereby contributing to a deeper understanding of the growth mechanisms of high-quality diamond.