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We report a systematic study of a pulsed 13.56 MHz transformer-coupled plasma over a range of frequencies from 200 Hz to 10 kHz using electrostatic probes. The time-resolved plasma density and electron temperature from the double-probe analysis were compared with single Langmuir probe results using both the orbital-motion-limited and radial-motion theories with sheath displacement corrections. The results were compared to a spatially-averaged model. Our experiments and analysis show that the double probes can be used reliably in pulsed plasma measurements. The good agreement between the equivalent resistance method and the nonlinear regression method indicates that the equivalent resistance method, which is faster and easier to automate, can be used effectively to analyse the double-probe data. The transient behaviours of the plasma density and electron temperature, although complicated, are in accord with the simple model of the discharge. The plasma density and the electron temperature can be decoupled in a pulsed plasma by adjusting the pulse parameters. This decoupling suggests that a pulsed plasma source can provide additional control for ion-assisted or neutral-assisted etching and deposition.

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Noncollisional heating and electron energy distributions in magnetically enhanced inductively coupled and helicon plasma sources Wave propagation and power deposition in magnetically enhanced inductively coupled and helicon plasma sources J.Large-area ion source combining microwaves with inductively coupled plasma Rev. Sci. Instrum. 71, 716 (2000)In this article, we report process damage studies using a low energy inductively coupled plasma-based neutral stream source. Low energy neutrals are generated by the surface reflection neutralization method. Quasistatic capacitance-voltage measurement results of this work demonstrate that this low energy neutral source, which provides controllable fast neutrals for cleaning applications, induces much less damage than a pulsed inductively coupled plasma source. Most of the neutral process damage is caused by ultraviolet photons escaping from the plasma source zone. The process-induced damage by fast neutrals increases as the reflector bias is lowered. The fast neutral process damage also increases with the rf power. Unlike the neutral process-induced damage, the damage induced by pulsed plasmas is found to be a function of both the gas composition and rf pulsed frequencies.