Etching mechanism of niobium in coaxial Ar/Cl{sub 2} radio frequency plasma

Journal Article · Sat Mar 21 00:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4914298· OSTI ID:22399298

Upadhyay, J.; Im, Do; Popović, S.; Vušković, L. ^[1]; Valente-Feliciano, A. -M.; Phillips, L. ^[2]

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1. Department of Physics, Center for Accelerator Science, Old Dominion University, Norfolk, Virginia 23529 (United States)
2. Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)

The understanding of the Ar/Cl{sub 2} plasma etching mechanism is crucial for the desired modification of inner surface of the three dimensional niobium (Nb) superconductive radio frequency cavities. Uniform mass removal in cylindrical shaped structures is a challenging task because the etch rate varies along the direction of gas flow. The study is performed in the asymmetric coaxial radio-frequency (rf) discharge with two identical Nb rings acting as a part of the outer electrode. The dependence of etch rate uniformity on pressure, rf power, dc bias, Cl{sub 2} concentration, diameter of the inner electrode, temperature of the outer cylinder, and position of the samples in the structure is determined. To understand the plasma etching mechanisms, we have studied several factors that have important influence on the etch rate and uniformity, which include the plasma sheath potential, Nb surface temperature, and the gas flow rate.

• OSTI ID: 22399298
• Journal Information: Journal of Applied Physics, Vol. 117, Issue 11; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ASYMMETRY
CHLORINE
CONCENTRATION RATIO
CYLINDRICAL CONFIGURATION
ELECTRODES
ETCHING
GAS FLOW
HIGH-FREQUENCY DISCHARGES
MODIFICATIONS
NIOBIUM
PLASMA POTENTIAL
PLASMA SHEATH
RADIOWAVE RADIATION
SUPERCONDUCTING CAVITY RESONATORS
SURFACES
THREE-DIMENSIONAL LATTICES