Downstream plasma transport and metal ionization in a high-powered pulsed-plasma magnetron

Journal Article · Sat Jun 14 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4878622· OSTI ID:22304186

Meng, Liang; Szott, Matthew M.; McLain, Jake T.; Ruzic, David N. ^[1]; Yu, He ^[1]

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1. Center for Plasma-Materials Interactions, Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

Downstream plasma transport and ionization processes in a high-powered pulsed-plasma magnetron were studied. The temporal evolution and spatial distribution of electron density (n{sub e}) and temperature (T{sub e}) were characterized with a 3D scanning triple Langmuir probe. Plasma expanded from the racetrack region into the downstream region, where a high n{sub e} peak was formed some time into the pulse-off period. The expansion speed and directionality towards the substrate increased with a stronger magnetic field (B), largely as a consequence of a larger potential drop in the bulk plasma region during a relatively slower sheath formation. The fraction of Cu ions in the deposition flux was measured on the substrate using a gridded energy analyzer. It increased with higher pulse voltage. With increased B field from 200 to 800 Gauss above racetrack, n{sub e} increased but the Cu ion fraction decreased from 42% to 16%. A comprehensive model was built, including the diffusion of as-sputtered Cu flux, the Cu ionization in the entire plasma region using the mapped n{sub e} and T{sub e} data, and ion extraction efficiency based on the measured plasma potential (V{sub p}) distribution. The calculations matched the measurements and indicated the main causes of lower Cu ion fractions in stronger B fields to be the lower T{sub e} and inefficient ion extraction in a larger pre-sheath potential.

• OSTI ID: 22304186
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 22; Other Information: (c) 2014 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
COMPUTERIZED SIMULATION
COPPER IONS
DEPOSITION
DIFFUSION
EFFICIENCY
ELECTRON DENSITY
EXPANSION
EXTRACTION
ION MOBILITY
IONIZATION
LANGMUIR PROBE
MAGNETIC FIELDS
MAGNETRONS
PLASMA
PLASMA POTENTIAL
PULSES
SPATIAL DISTRIBUTION
SUBSTRATES
VELOCITY