Geometrical aspects of a hollow-cathode planar magnetron

Journal Article · Sat May 01 04:00:00 EDT 1999 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.873421· OSTI ID:337523

Wang, Z; Cohen, S A ^[1]

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1. Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey 08543 (United States)

A hollow-cathode planar magnetron (HCPM), built by surrounding a planar sputtering-magnetron cathode with a hollow-cathode structure (HCS) [Z. Wang and S. A. Cohen, J. Vac. Sci. Technol. A {bold 17}, 77 (1999)], is operable at substantially lower pressures than its planar-magnetron counterpart. HCPM operational parameters depend on the inner diameter {ital D} and length {ital L} of its cylindrical HCS. Only when {ital L} is greater than L{sub 0}, a critical length, is the HCPM operable in the new low-pressure regime. The critical length varies with HCS inner diameter {ital D}. Explanations of the lower operational pressure regime, critical length, and plasma shape are proposed and compared with a one-dimension diffusion model for energetic electron transport. At pressures above 1 mTorr, Bohm diffusion (temperature{congruent}primary electron energy), with an ambipolar constraint, can explain the ion{endash}electron pair creation required to sustain the discharge. At the lowest pressure, {approximately}0.3 mTorr, collision-limited diffusion creates fewer ion{endash}electron pairs than required for steady state and therefore cannot explain the experimental data. The critical length L{sub 0} is consistent with the magnetization length of the primary electrons. {copyright} {ital 1999 American Institute of Physics.}

• OSTI ID: 337523
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 6; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CATHODES
CHARGED-PARTICLE TRANSPORT
GEOMETRY
HOLLOW CATHODES
MAGNETIZATION
MAGNETRONS
PRESSURE DEPENDENCE
SPUTTERING