No abstract

In this work, an analytical hybrid model, which consists of an analytical electromagnetic model and a global model, is developed to investigate the E to H mode transition in a planer inductively coupled plasma. By employing the hybrid model, the effect of discharge frequency, oxygen content, and gas pressure on the E to H mode transition is investigated. The results show that the electron density increases rapidly with coil current when the discharge shifts to the H mode, and the mode transition becomes smoother and occurs at lower current when the driving frequency is higher. As oxygen content increases, the electron density declines, and the threshold current for the mode transition exhibits a rising trend. The evolution of the threshold current with pressure is nonlinear; i.e., it decreases first and then increases, and the minimum value varies with discharge frequency. In addition, the plasma composition also changes during the E to H mode transition; i.e., all the charged species densities increase with coil current, except the O− density, which varies nonlinearly, and this indicates the decreasing electronegativity in the H mode. The results obtained in this work are helpful for understanding the effect of different discharAr/O2ge parameters on the E to H mode transition in Ar/O2 inductive discharges.

In the etching process, a bias source is usually applied to the bottom electrode in inductively coupled plasmas (ICPs) to achieve independent control of the ion flux and ion energy. In this work, a hybrid model, which consists of a global model combined bi-directionally with a fluid sheath model, is employed to investigate the dual-frequency (DF) bias effect on the inductively coupled Cl2plasmas under different pressures. The results indicate that the DC self-bias voltage developed on the biased electrode is approximately a linear function of the phase shift between the fundamental frequency and its second harmonic, and the value only varies slightly with pressure. Therefore, the ion energy on the bottom electrode can be modulated efficiently by the bias voltage waveform, i.e., the fluctuation of the ion energy with phase shift is about 40% for all pressures investigated. Besides, the ion energy and angular distribution functions (IEADFs) in DF biased inductive discharges is complicated, i.e., the IEADFs exhibits a four-peak structure under certain phase shift values. Although the species densities and ion fluxes also evolve with phase shift, the fluctuations are less obvious, especially for Cl2+ ions at low pressure. In conclusion, the independent control of the ion energy and ion flux are realized in DF biased ICPs, and the results obtained in this work are of significant importance for improving the etching process.