Reversal of the asymmetry in a cylindrical coaxial capacitively coupled Ar/Cl2 plasma

Upadhyay, Janardan; Im, Do; Popović, Svetozar; Vušković, Leposava; Valente-Feliciano, Anne -Marie; Phillips, Larry

doi:10.1116/1.4932562

Title: Reversal of the asymmetry in a cylindrical coaxial capacitively coupled Ar/Cl₂ plasma

Abstract

The reduction of the asymmetry in the plasma sheath voltages of a cylindrical coaxial capacitively coupled plasma is crucial for efficient surface modification of the inner surfaces of concave three-dimensional structures, including superconducting radio frequency cavities. One critical asymmetry effect is the negative dc self-bias, formed across the inner electrode plasma sheath due to its lower surface area compared to the outer electrode. The effect on the self-bias potential with the surface enhancement by geometric modification on the inner electrode structure is studied. The shapes of the inner electrodes are chosen as cylindrical tube, large and small pitch bellows, and disc-loaded corrugated structure (DLCS). The dc self-bias measurements for all these shapes were taken at different process parameters in Ar/Cl₂ discharge. Lastly, the reversal of the negative dc self-bias potential to become positive for a DLCS inner electrode was observed and the best etch rate is achieved due to the reduction in plasma asymmetry.

Authors:

Upadhyay, Janardan ^[1]; Im, Do ^[1]; Popović, Svetozar ^[1]; Vušković, Leposava ^[1]; Valente-Feliciano, Anne -Marie ^[2]; Phillips, Larry ^[2]

Old Dominion Univ., Norfolk, VA (United States)
Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

Publication Date:: Thu Oct 08 00:00:00 EDT 2015

Research Org.:: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Nuclear Physics (NP)

OSTI Identifier:: 1245208

Report Number(s):: JLAB-ACC-15-2206; DOE/OR/23177-3647
Journal ID: ISSN 0734-2101; JVTAD6

Grant/Contract Number:: AC05-06OR23177

Resource Type:: Accepted Manuscript

Journal Name:: Journal of Vacuum Science and Technology A

Additional Journal Information:: Journal Volume: 33; Journal Issue: 6; Journal ID: ISSN 0734-2101

Publisher:: American Vacuum Society

Country of Publication:: United States

Language:: English

Subject:: 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; plasma etching; SRF cavity; asymmetric discharge; coaxial rf discharge; electrodes; direct current power transmission; high pressure; plasma sheaths

Citation Formats


                    Upadhyay, Janardan, Im, Do, Popović, Svetozar, Vušković, Leposava, Valente-Feliciano, Anne -Marie, and Phillips, Larry. Reversal of the asymmetry in a cylindrical coaxial capacitively coupled Ar/Cl2 plasma.  United States: N. p., 2015. 
Web.  doi:10.1116/1.4932562.

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                    Upadhyay, Janardan, Im, Do, Popović, Svetozar, Vušković, Leposava, Valente-Feliciano, Anne -Marie, & Phillips, Larry. Reversal of the asymmetry in a cylindrical coaxial capacitively coupled Ar/Cl2 plasma.  United States.  https://doi.org/10.1116/1.4932562

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                    Upadhyay, Janardan, Im, Do, Popović, Svetozar, Vušković, Leposava, Valente-Feliciano, Anne -Marie, and Phillips, Larry. Thu .  
"Reversal of the asymmetry in a cylindrical coaxial capacitively coupled Ar/Cl2 plasma".  United States.  https://doi.org/10.1116/1.4932562.  https://www.osti.gov/servlets/purl/1245208.

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@article{osti_1245208,

  title        = {Reversal of the asymmetry in a cylindrical coaxial capacitively coupled Ar/Cl2 plasma},

  author       = {Upadhyay, Janardan and Im, Do and Popović, Svetozar and Vušković, Leposava and Valente-Feliciano, Anne -Marie and Phillips, Larry},

  abstractNote = {The reduction of the asymmetry in the plasma sheath voltages of a cylindrical coaxial capacitively coupled plasma is crucial for efficient surface modification of the inner surfaces of concave three-dimensional structures, including superconducting radio frequency cavities. One critical asymmetry effect is the negative dc self-bias, formed across the inner electrode plasma sheath due to its lower surface area compared to the outer electrode. The effect on the self-bias potential with the surface enhancement by geometric modification on the inner electrode structure is studied. The shapes of the inner electrodes are chosen as cylindrical tube, large and small pitch bellows, and disc-loaded corrugated structure (DLCS). The dc self-bias measurements for all these shapes were taken at different process parameters in Ar/Cl2 discharge. Lastly, the reversal of the negative dc self-bias potential to become positive for a DLCS inner electrode was observed and the best etch rate is achieved due to the reduction in plasma asymmetry.},

  doi          = {10.1116/1.4932562},

  journal      = {Journal of Vacuum Science and Technology A},

  number       = 6,

  volume       = 33,

  place        = {United States},

  year         = {Thu Oct 08 00:00:00 EDT 2015},

  month        = {Thu Oct 08 00:00:00 EDT 2015}

}

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Works referencing / citing this record:

Effect of self-bias on cylindrical capacitive discharge for processing of inner walls of tubular structures—Case of SRF cavities
journal, August 2018

Upadhyay, J.; Peshl, J.; Popović, S.
AIP Advances, Vol. 8, Issue 8
DOI: 10.1063/1.5045692

Argon metastable and resonant level densities in Ar and Ar/Cl2 discharges used for the processing of bulk niobium
journal, September 2019

Peshl, Jeremy; McNeill, Roderick; Sukenik, Charles I.
Journal of Applied Physics, Vol. 126, Issue 10
DOI: 10.1063/1.5115043

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Similar Records

Title: Reversal of the asymmetry in a cylindrical coaxial capacitively coupled Ar/Cl2 plasma

Abstract

Citation Formats

Effect of self-bias on cylindrical capacitive discharge for processing of inner walls of tubular structures—Case of SRF cavities journal, August 2018

Argon metastable and resonant level densities in Ar and Ar/Cl2 discharges used for the processing of bulk niobium journal, September 2019

Title: Reversal of the asymmetry in a cylindrical coaxial capacitively coupled Ar/Cl₂ plasma

Effect of self-bias on cylindrical capacitive discharge for processing of inner walls of tubular structures—Case of SRF cavities
journal, August 2018

Argon metastable and resonant level densities in Ar and Ar/Cl2 discharges used for the processing of bulk niobium
journal, September 2019