NUMERICAL INVESTIGATION ON THE CHARACTERISTICS OF POWER DEPOSITION IN HELICON PLASMA

Helicon plasma has significant application value in semiconductor manufacturing and electric propulsion fields, with its advantages of high ionization rate and high density. The scientific challenge of existing research is difficult to analyze the power deposition mechanism under the multi-wave coupling modes. This study systematically explores the competition rules of the eigenmodes of Trivelpiece-Gould (TG) waves and Helicon (H) waves and their power deposition characteristics in low and high-order wave coupling modes based on HELIC numerical simulation. By constructing a parameterized radial density profile model (with the gradient parameter s ranging from 2.1 to 3.4 and the peaking parameter t ranging from 1.8 to 2.5), and combining with the numerical method of self-consistently solving the coupled Maxwell-Boltzmann equations, the dynamic reconstruction of the multi-wave mode hopping process has been achieved. The results show that in the low-order wave mode (W1, ne = 2.0 ? 1012 cm?3), TG waves contribute 61.8% of the boundary electron heating efficiency through the radial electric field localization mechanism, while the power deposition in the central region of H waves only accounts for 38.2%; when the high-order modes (W2-W4, ne = 4.0 ? 1012 – 1.1 ? 1013 cm?3) are excited, the edge damping effect of TG waves leads to a sudden drop in its power contribution to 16.5%, and at this time, H waves achieve 83.5% of the power deposition in the central region through axial standing wave resonance, and induce a modal transition of the plasma density distribution from the peripheral peak formation (s = 2.1) to central aggregation (s = 3.4). The research results provide important theoretical support for the precise regulation of the parameter distribution and mode selection of helicon plasmas. It has direct guiding significance for optimizing the uniformity of semiconductor etching and the specific impulse performance of electric thrusters.