Negative ion kinetics in RF glow discharges

Journal Article · Tue Apr 01 04:00:00 EST 1986 · IEEE Trans. Plasma Sci.; (United States)

DOI:https://doi.org/10.1109/TPS.1986.4316511· OSTI ID:5815728

Gottscho, R A; Gacbe, C E

Using temporally and spatially resolved laser spectroscopy, the authors have determined the identities, approximate concentrations, effects on the local field, and kinetics of formation and loss of negative ions in RF discharges. CI/sup -/ and BCI/sub 3//sup -/ are the dominant negative ions found in low-frequency discharges through CI/sub 2/ and BCI/sub 3/, respectively. The electron affinity for CI is measured to be 3.6118 +- 0.0005 eV. Negative ion kinetics are strongly affected by application of the RF field. Formation of negative ions by attachment of slow electrons in RF discharges is governed by the extent and duration of electron energy relaxation. Similarly, destruction of negative ions by collisional detachment and field extraction is dependent upon ion energy modulation. Thus, at low frequency, the anion density peaks at the beginning of the anodic and cathodic half-cycles after electrons have attached but before detachment and extraction have had time to occur. At higher frequencies, electrons have insufficient time to attach before they are reheated and the instantaneous anion density in the sheath is greatly reduced. When the negative ion density is comparable to the positive ion density, the plasma potential is observed to lie below the anode potential, double layers form between sheath and plasma, and anions and electrons are accelerated by large sheath fields to electrode surfaces.

• Research Organization: AT and T Bell Laboratories, Murray Hill, NJ 07974
• OSTI ID: 5815728
• Journal Information: IEEE Trans. Plasma Sci.; (United States), Journal Name: IEEE Trans. Plasma Sci.; (United States) Vol. PS-14:2; ISSN ITPSB
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420800* -- Engineering-- Electronic Circuits & Devices-- (-1989)
AFFINITY
ANODES
BORON CHLORIDES
BORON COMPOUNDS
CATHODES
CHARGED PARTICLES
CHLORIDES
CHLORINE COMPOUNDS
CHLORINE IONS
COLLISIONS
ELECTRIC DISCHARGES
ELECTRODES
ELECTRONS
ELEMENTARY PARTICLES
ENERGY RANGE
EV RANGE
EV RANGE 01-10
FERMIONS
GLOW DISCHARGES
HALIDES
HALOGEN COMPOUNDS
ION COLLISIONS
ION DENSITY
ION MOBILITY
IONS
LASER SPECTROSCOPY
LEPTONS
MOBILITY
PARTICLE MOBILITY
PLASMA
RF SYSTEMS
SPECTROSCOPY