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Experimental study of transition from electron beam to rf power controlled plasma in DF CCP in argon with additional ionization by an electron beamстатья Исследовательская статья
- Авторы: Zotovich Alexey, Lopaev Dmitry, Bogdanova Maria, Zyryanov S.M., Rakhimov A.T.
- Журнал: Journal of Physics D - Applied Physics
- Том: 55
- Номер: 31
- Год издания: 2022
- Издательство: IOP Publishing
- Местоположение издательства: [Bristol, UK], England
- DOI: 10.1088/1361-6463/ac6712
- Аннотация: Rf plasma with additional ionization by an electron beam (e-beam) is considered as a possible method for independent control of plasma density, mean electron and ion energies. In this study, spatial transition from e-beam to rf power controlled dual-frequency capacitively coupled plasma (DFCCP) was studied using the following movable diagnostics: Langmuir and hairpin probes, retarding field energy analyzer and optical emission spectroscopy. The beam (1.1-1.4 keV) is generated by a run-away electron beam module placed near the plasma chamber wall, while the plasma transition is caused by e-beam degradation with the distance from the e-beam module. The study was conducted in Ar at 200 mTorr and 400 mTorr gas pressures in 81 & 12 MHz DFCCP. When the e-beam is on, significant decrease of the mean electron energy is observed, from 6 eV in the rf plasma down to 0.2 – 0.8 eV in the e-beam plasma. The e-beam also changes the shape of electron energy probability function (EEPF): from Druyvesteyn-like in rf plasma it turns into Maxwellian-like. When both e-beam and rf power are applied the mean electron energy increase and electron density decrease with the distance from the e-beam module are observed due to the beam degradation. The ion energy distribution at the bottom electrode in rf plasma is peaked at 25 – 30 eV and shifted down to a few eV in e-beam plasma. As in conventional DFCCP, the ion energy distribution can be fine-tuned by application of a low-frequency rf bias. However, the use of an e-beam allows reducing the range of ion energies down to a few eV, which cannot be achieved in conventional rf discharges.
- Добавил в систему: Зотович Алексей Иванович