Spatial transport and afterglow uniformity in RF inductively coupled multi-driven remote plasma sources

This paper investigates the discharge characteristics in a radio frequency inductively coupled multi-driven remote plasma source using double-probe experimental diagnostics and two-dimensional fluid simulation. It is found that the plasma density decreases from the center of the driver to the afterglow region due to the diffusion transport. As the pressure decreases, the plasma density gradually decreases in the driver but increases in the afterglow region. It indicates that the enhanced nonlocality at low pressure facilitates the plasma transport from the driver to the afterglow region. For double-driven discharges, the plasma density in the afterglow region can be effectively increased by reducing the spacing between the two drivers. The adjustment for the power, pressure, or spacing between the two drivers achieves the improvement of the plasma uniformity in the afterglow region. The plasma uniformity was barely improved by four drivers connected to one power source but markedly increased with two power sources.