| AVS 57th International Symposium & Exhibition | |
| Plasma Science and Technology | Wednesday Sessions |
| Session PS-WeM |
| Session: | Plasma Surface Interactions (Fundamentals & Applications) I |
| Presenter: | P. 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. In conventional plasma processing, employing a sinusoidal substrate electrode voltage, the ion energy distribution (IED) is often very broad. However, as film dimensions approach the atomic level, control of the IED becomes critical. For example, selectivity considerations often dictate a narrow IED with a specified peak energy. In this work, semi-analytical models and particle-in-cell (PIC) simulations are employed to achieve “designer” IEDs, i.e., distributions with a desired shape and energy spread. This is accomplished by applying tailored voltage waveforms on the substrate electrode (spike, staircase, judiciously distorted square wave, etc.). Such waveforms can provide, for example, nearly mono-energetic IEDs or other desired shapes. Semi-analytic model results are compared with those of PIC simulation to identify the range of validity of the semi-analytic model. Predicted IEDs are also compared with experimental data under both collisional and collisionless sheath conditions. Strategies to control the energy flux of bombarding ions or to distribute the total energy flux to different energies will also be discussed.
Work supported by DoE Plasma Science Center and NSF.