Study of the neutral gas flow on discharges of capacitively coupled plasma in a PECVD reactor

A two-dimensional fluid model is established to describe the argon discharges coupled with the neutral gas flow in a capacitively coupled plasma reactor. Two different configurations are designed to investigate the influence of the gas flow direction on discharges. The radial distributions of ion density and ion flux are paid for a special attention. It is found that when the gas flow is mainly axial, the ion density and ion flux increases significantly with the increase of inlet velocity, and the radial uniformity of their distributions changes little. When the gas flow is mainly radial, there are two peaks in the ion density distributions. With the increase of velocity, the left peak is weakened and the right peak is enhanced. It is also found that with the increase of the outlet pressure, both the ion density and ion flux increase greatly, but the influence of the gas flow on discharges decreases distinctly. Moreover, it is shown that the density peak moves from side to center at high pressure when the neutral gas flow is mainly in the axial direction.

► When the gas flow is radial, there are two peaks in the ion density distribution.
► With the increase of inlet velocity, the left peak of ion density is weakened.
► With the increase of inlet velocity, the right peak of ion density is enhanced.
► With the increase of pressure the role of gas flow on discharges weakens greatly.
► The density peak moves from side to center at high pressure.