| AVS 58th Annual International Symposium and Exhibition | |
| Plasma Science and Technology Division | Friday Sessions |
| Session PS-FrM |
| Session: | Plasma Modeling |
| Presenter: | Paola Diomede, University of Houston |
| Authors: | P. Diomede, University of Houston D.J. Economou, University of Houston V.M. Donnelly, University of Houston |
| Correspondent: | Click to Email |
The energy of ions bombarding the substrate is critical in plasma etching and deposition of thin films, especially when precise etching without damage is required. The ion energy distribution (IED) may be controlled by applying “tailored” bias voltages on the substrate, or on nearby electrodes immersed in the plasma. A Particle-in-Cell simulation with Monte Carlo Collisions (PIC-MCC) was conducted of the application of DC voltage steps (and staircases) on an electrode, during the afterglow of a capacitively-coupled pulsed argon discharge, to control the energy of ions incident on the counter-electrode holding the wafer. Staircase voltage waveforms with selected amplitudes and durations resulted in ion energy distributions with distinct narrow peaks, having controlled peak energies and fraction of ions under each peak. A semi-analytical model was also employed to achieve “tailored” IEDs, i.e., distributions with a desired shape and energy spread (for example a nearly-monoenergetic IED with given FWHM). This was again accomplished by applying judicious voltage waveforms on the substrate electrode. Predicted IEDs were compared with experimental data. Strategies to control the energy flux of bombarding ions or to distribute the total ion energy flux to different energies were identified.
Work supported by DoE Plasma Science Center and NSF.