Comparison between Dual Radio Frequency- and Pulse-Driven Sheath near Insulating Substrates

We carry out a comparison between the characteristics of radio frequency- and pulse-sheath near insulating substrates driven by dual frequency (DF) sources making use of the fluid model in which the self-bias voltage on the electrode is obtained consistently under a current balance condition. The results show that the combination of the higher and lower frequency source
modulate the characteristics of the radio-frequency- and pulse-sheath: the higher frequency makes the physical quantities oscillate fast while the slow oscillating contour of variation in physical quantities is modulated by the lower frequency source. However, there are some differences between the capacity of mitigating the charging effects on the surface of the insulator, i.e., the pulsed driven plasma gains an advantage over the radio-frequency driven one because the `off' state of the pulse allow more electrons to reach the insulating surface to neutralize the positive charge due to the incident ion as the pulse being in the pulse's duty. In addition, the ion energy distribution (IED) bombarding the surface of the insulator has a range of energy for the
radio-frequency bias while that for the pulse bias is discontinuous.