中国物理B ›› 2018, Vol. 27 ›› Issue (4): 45202-045202.doi: 10.1088/1674-1056/27/4/045202

• PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES • 上一篇    下一篇

Phase shift effects of radio-frequency bias on ion energy distribution in continuous wave and pulse modulated inductively coupled plasmas

Chan Xue(薛婵), Fei Gao(高飞), Yong-Xin Liu(刘永新), Jia Liu(刘佳), You-Nian Wang(王友年)   

  1. 1. Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams(Ministry of Education), School of Physics, Dalian University of Technology, Dalian 116024, China;
    2. Shanghai Institute of Space Propulsion, Shanghai 201112, China
  • 收稿日期:2017-12-03 修回日期:2018-01-12 出版日期:2018-04-05 发布日期:2018-04-05
  • 通讯作者: Fei Gao, You-Nian Wang E-mail:fgao@dlut.edu.cn;ynwang@dlut.edu.cn
  • 基金资助:

    Project supported by the Important National Science and Technology Specific Project, China (Grant No. 2011ZX02403-001), the National Natural Science Foundation of China (Grand No. 11675039), and the Fundamental Research Funds for the Central Universities, China (Grand No. DUT16LK06).

Phase shift effects of radio-frequency bias on ion energy distribution in continuous wave and pulse modulated inductively coupled plasmas

Chan Xue(薛婵)1, Fei Gao(高飞)1, Yong-Xin Liu(刘永新)1, Jia Liu(刘佳)2, You-Nian Wang(王友年)1   

  1. 1. Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams(Ministry of Education), School of Physics, Dalian University of Technology, Dalian 116024, China;
    2. Shanghai Institute of Space Propulsion, Shanghai 201112, China
  • Received:2017-12-03 Revised:2018-01-12 Online:2018-04-05 Published:2018-04-05
  • Contact: Fei Gao, You-Nian Wang E-mail:fgao@dlut.edu.cn;ynwang@dlut.edu.cn
  • Supported by:

    Project supported by the Important National Science and Technology Specific Project, China (Grant No. 2011ZX02403-001), the National Natural Science Foundation of China (Grand No. 11675039), and the Fundamental Research Funds for the Central Universities, China (Grand No. DUT16LK06).

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摘要：

A retarding field energy analyzer (RFEA) is used to measure the time-averaged ion energy distributions (IEDs) on the substrate in both continuous wave (CW) and synchronous pulse modulated radio-frequency (RF) inductively coupled Ar plasmas (ICPs). The effects of the phase shift θ between the RF bias voltage and the RF source on the IED is investigated under various discharge conditions. It is found that as θ increases from 0 to π, the IED moves towards the low-energy side, and its energy width becomes narrower. In order to figure out the physical mechanism, the voltage waveforms on the substrate are also measured. The results show that as θ increases from 0 to π, the amplitude of the voltage waveform decreases and, meanwhile, the average sheath potential decreases as well. Specifically, the potential drop in the sheath on the substrate exhibits a maximum value at the same phase (i.e., θ=0) and a minimum value at the opposite phase (i.e., θ=π). Therefore, when ions traverse across the sheath region above the substrate, they obtain less energies at lower sheath potential drop, leading to lower ion energy. Besides, as θ increases from π to 2π, the IEDs and their energy widths change reversely.

关键词: ion energy distribution, phase shift, synchronous pulse modulated, inductively coupled plasmas

Abstract:

A retarding field energy analyzer (RFEA) is used to measure the time-averaged ion energy distributions (IEDs) on the substrate in both continuous wave (CW) and synchronous pulse modulated radio-frequency (RF) inductively coupled Ar plasmas (ICPs). The effects of the phase shift θ between the RF bias voltage and the RF source on the IED is investigated under various discharge conditions. It is found that as θ increases from 0 to π, the IED moves towards the low-energy side, and its energy width becomes narrower. In order to figure out the physical mechanism, the voltage waveforms on the substrate are also measured. The results show that as θ increases from 0 to π, the amplitude of the voltage waveform decreases and, meanwhile, the average sheath potential decreases as well. Specifically, the potential drop in the sheath on the substrate exhibits a maximum value at the same phase (i.e., θ=0) and a minimum value at the opposite phase (i.e., θ=π). Therefore, when ions traverse across the sheath region above the substrate, they obtain less energies at lower sheath potential drop, leading to lower ion energy. Besides, as θ increases from π to 2π, the IEDs and their energy widths change reversely.

Key words: ion energy distribution, phase shift, synchronous pulse modulated, inductively coupled plasmas

中图分类号:  (Discharges for spectral sources)

  • 52.80.Yr
52.70.-m (Plasma diagnostic techniques and instrumentation) 52.20.Hv (Atomic, molecular, ion, and heavy-particle collisions) 52.40.Kh (Plasma sheaths)