Wave Propagation and Plasma Uniformity in An Electron Cyclotron Resonance Plasma

This study examined microwave propagation and plasma uniformity in the mode of introduced microwaves and the discharged gases. TE_n-mode microwaves are almost all absorbed close to the electron cyclotron resonance (ECR) region. Conversely, TM₀₁-mode microwaves are mainly absorbed upstream from the ECR region. Accordingly, in the case of TE_irmode microwave, the plasma uniformity strongly depends on the magnetic field profiles and the position of the resonance region. TM_ormode microwave plasma is generated uniformly at any magnetic field and any position. Moreover, the microwave propagation states are changed on the discharged gases. TE_n-mode microwaves are gradually absorbed upstream from the ECR region in CHF₃ gas plasma, whereas N₂gas plasma causes microwave absorption close to the ECR region. Then, the CHF₃ plasma results in a uniform ion current density, in comparison with the result for N₂ gas plasma. This is considered to be due to electron temperature differences in the plasmas.