| AVS 64th International Symposium & Exhibition | |
| Plasma Science and Technology Division | Tuesday Sessions |
| Session PS-TuP |
| Session: | Plasma Science and Technology Poster Session |
| Presenter: | Ya-Ming Chen, University of Houston |
| Authors: | Y.-M. Chen, University of Houston R. Sawadichai, University of Houston V.M. Donnelly, University of Houston D.J. Economou, University of Houston |
| Correspondent: | Click to Email |
Precise control of the ion flux and ion energy distribution (IED) is crucial for advanced plasma processes that require high selectivity and minimum substrate damage. To neutralize the space charge of the ion beam extracted from a plasma, hot filaments, emitting electrons thermionically, are strategically placed on the downstream side of the extraction grid. Charge neutralization prevents spreading of the ion beam by Coulomb collisions among the ions. This work reports our observation that a self-neutralized ion beam can be obtained when the beam is extracted in the afterglow of a pulsed plasma. Specifically, a nearly monoenergetic ion beam was realized by applying a synchronous DC bias on an electrode in contact with the plasma (so-called boundary electrode) during a specified time window in the afterglow of a pulsed plasma. The ion beam flux in the pulsed plasma case was much higher than that in a continuous wave plasma under comparable conditions. Retarding Field Energy Analyzer measurements of the ion flux and IED with varying control parameters (including plasma pulsing frequency, and the time delay in the afterglow before a DC bias was applied on the boundary electrode) were performed to provide a plausible explanation of the system behavior.
Work supported by NSF.