ROLE OF EXCITATION-FREQUENCY IN A LOW-PRESSURE, INDUCTIVELY-COUPLED RADIOFREQUENCY, MAGNETIZED PLASMA

We have experimentally studied the role of the excitation frequency f(rf) in a low-pressure, inductively coupled radio-frequency (rf), magnetized plasma. Planar Langmuir probe measurements of the electron energy distribution function and the plasma density n(e) clearly demonstrate a sudden change in the nature of plasma-rf coupling as f(rf) approaches the electron cyclotron frequency f(ce) from below or above. The observed mode change is qualitatively explained by different wave coupling mechanism for f(rf) < f(ce) and f(rf) > f(ce). These observations could have important applications for plasma processing.