Spatial structure of radio-frequency capacitive discharge plasma with ring-shaped hollow electrode using Ar and O2 mixture gases

The spatial structures of plasma parameters in a radio-frequency capacitive discharge plasma with a ring-shaped hollow electrode operated in argon were measured at various oxygen gas concentrations for plasma processing by moving a cylindrical Langmuir probe. Their distinctive profiles are obtained...

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Bibliographic Details
Published in:Journal of physics. D, Applied physics Applied physics, 2019-07, Vol.52 (35)
Main Authors: Ohtsu, Yasunori, Takasaki, Masaya, Schulze, Julian
Format: Article
Language:English
Subjects:
capacitive discharge
double layer
high-density plasma
negative ions
ring-shaped hollow electrode
spatial structure
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Summary:The spatial structures of plasma parameters in a radio-frequency capacitive discharge plasma with a ring-shaped hollow electrode operated in argon were measured at various oxygen gas concentrations for plasma processing by moving a cylindrical Langmuir probe. Their distinctive profiles are obtained around the ring-shaped hollow trench. The electron temperature Te at the hollow trench of radial position r  =  37.5 mm has a peak value at an O2 gas concentration of 0%, whereas at O2 gas concentrations of 5 and 10% Te decreases everywhere except for positions close to the hollow trench. The plasma potential Vs at an O2 gas concentration of 0% is higher than that at O2 gas concentrations of 5% and 10%. The electron density ne has a peak value at the hollow trench at all O2 gas concentrations and decreases with increasing O2 gas concentration. Their axial profiles indicate unique distributions around the hollow inlet at a radial position of r  =  37.5 mm, while at a radial position of r  =  0 the profiles are almost uniform. It is found that a double layer is formed from the axial profiles of the plasma potential at r  =  37.5 mm for all oxygen gas concentrations.
ISSN:0022-3727
1361-6463
DOI:10.1088/1361-6463/ab2862