A weak DC magnetic field is applied to an immersed helical resonator antenna in an RF plasma to study the effects of magnetic insulation on potential differences between plasma and antenna within the vacuum chamber. Past research suggests a link between minimizing antenna potential and mitigating self-sputtering effects within the chamber to minimize debris creation. Alteration of particle flux ratios at the sheath boundary affects this potential difference. A simplified theory of cross-field diffusion shows the trend of decreasing potential as a function of the Hall parameter. A Langmuir probe obtains experimental evidence showing a continuously decreasing potential at lower Hall parameters than theory predicts. Due to RF biasing of the plasma, alteration of the diffusion coefficient is not the only variable affecting the potential difference between plasma and antenna. Since the experiments focus on the transitional state between collisional and magnetized plasmas, inclusion of collisional physics in the next iteration of theory may predict trends in the potential difference between plasma and antenna potential more accurately. The normalized potential difference between plasma and antenna is shown to decrease by 35% over a ten-fold increase in the Hall parameter where simplified theory predicts no change.
ASJC Scopus subject areas
- Condensed Matter Physics