Plasma injection with helicon sources

An exhaustive set of measurements has been made to find the optimum conditions for plasma injection into a processing chamber using small helicon sources with low magnetic fields B. It is found that the plasma density decreases, rather than increases, with B, as in normal helicon discharges. The design of the field coil and flange caused this effect; with a different design, normal operation was obtained. This experiment provides data on the area coverage of individual helicon discharges for the design of large-area, distributed plasma sources.