Two-dimensional fluid simulations of sawtooth waveform pulsed inductively coupled Ar/O₂ plasma discharges

Abstract In this work, the effect of sawtooth waveforms on the plasma properties in pulsed inductively coupled Ar/O 2 discharges is investigated using a two-dimensional fluid model. It is shown that by increasing the slope of sawtooth waveforms with a constant delivery of RF power during the pulse-on phase, the power rises steadily, and the electron density at the beginning of the pulse-on period is higher, which helps to suppress the overshoot phenomenon in the electron temperature. The peak of the potential when the power is turned on also disappears at larger slopes, indicating that the ion bombarding energy on the wafer is lowered. Since the ion flux above the wafer during the first half of the pulse period is the lowest under this condition, the damage to the wafer caused by energetic ion bombardment could be effectively reduced when operating without bias sources. The effects of duty cycle and pulse frequency on the plasma parameters are also investigated, and the results show that increasing the duty cycle is beneficial to suppress the overshoot in the electron temperature and potential, while the influence of pulse frequency is limited.