| AVS 57th International Symposium & Exhibition | |
| Plasma Science and Technology | Thursday Sessions |
| Session PS-ThP |
| Session: | Plasma Science and Technology Poster Session |
| Presenter: | W. Zhu, University of Houston |
| Authors: | W. Zhu, University of Houston H. Shin, University of Houston L. Xu, University of Houston V.M. Donnelly, University of Houston D.J. Economou, University of Houston |
| Correspondent: | Click to Email |
A novel plasma reactor was designed and built to control the electron energy distribution function (EEDF) in the plasma, as well as the ion energy distribution (IED) and ion angular distribution (IAD) on the substrate electrode. The main inductively coupled plasma (ICP) source has a Faraday shield to minimize the RF component of the plasma potential. The substrate electrode and another electrode in contact with the plasma (boundary electrode) can be biased independently with DC or RF voltages to influence the IED and IAD. A second tandem ICP plasma source may be used to inject a secondary plasma or metastable atoms to the main source, to influence the EEDF. A continuous wave argon plasma in the main ICP was characterized with a Langmuir probe (LP), with and without the Faraday shield installed. With the Faraday shield, the DC value of the plasma potential decreased from 25 to 17 V, and the corresponding peak-to-peak amplitude of the RF oscillation dropped from ~15-20 V to ~0.8-1.5 V, compared to the case without the Faraday shield. A low plasma potential is critical for certain processes such as atomic layer etching with monolayer precision. The electron “temperature” as well as the ion and electron densities were measured for a range of powers and pressures. The plasma density was 1.5×10-12cm-3 at 40 mtorr and 300 W. The EEPF was also measured with the LP; comparisons with EEPFs extracted using trace rare gas-optical emission spectroscopy (TRG-OES) will be presented. In addition to argon, oxygen and krypton plasmas were studied and their similarities and differences with the argon plasma will be shown. Control of the plasma potential and hence energy of ions impacting surfaces was achieved by applying a positive DC voltage to a boundary electrode immersed in the plasma. Finally, preliminary results of plasma injection from the secondary to the main plasma source and its effect on the EEDF will be presented.
Work supported by the Department of Energy Plasma Science Center and NSF