Energy distribution of heavy particles generated in the cathode fall of glow discharge

Heavy particles bombarding the cathode surface in a glow discharge produce sputtering which liberates cathode material which then appears in the plasma phase in the vicinity of the cathode. The intensity of light emission from fundamental gas atoms depends linearly on the discharge current and this dependence can be explained if it is assumed that these intensities are proportional to the densities of the gas and electron current density. The electron/molecule excitation of sputtered material in the plasma phase is the main source of the light emitted by elements of the cathode. The intensity of light emission from this cathode material in the plasma depends parabolically on the discharge current density. This dependence can be explained if the intensity is assumed to be proportional to the densities of both the electron current and the stream of sputtered particles leaving the cathode surface. The density of the sputtered particles is in turn dependent on the energy of bombarding particles. The excitation of the sputtered material due to fast particle interaction with the cathode bulk seems to be a less important mechanism of light emission.

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“…(see the work of Wronski et al [11]). Usually we can assume the cathode fall voltage U cf to be equal to the anode-cathode voltage U ca .…”

Section: Model (Ii)mentioning

confidence: 99%

Studies of light emission from cathode material in the plasma phase of a glow discharge

Wroński¹,

Sielanko²,

Sullivan³

1996

J. Phys. D: Appl. Phys.

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“…It is important to remark the significance of including charge-exchange processes, which generates a cascade of fast neutrals atoms that bombard the cathode. [8][9][10] When the gas pressure increases, the behavior of the energy distribution corresponding to the fast neutrals is similar to that of the ions.…”

Section: A Generation Of the Particles That Bombard The Cathodementioning

confidence: 90%

Radial profile of energetic particles bombarding the substrate in a glow discharge

Moreno-Marı́n

Abril

García-Molina

1999

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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We have analyzed in an interrelated way the main processes that occur in a glow discharge system: generation of the energetic particles that strike the cathode, emission of sputtered and reflected atoms from the cathode, and transport of these particles through the plasma, until their eventual arrival to the substrate. As an output of our calculations we have obtained the radial profiles of the energy and the number of particles that reach the substrate, as a function of the geometrical characteristics and pressure of the discharge. Our results show that the main part of the energy deposited in the substrate comes from the reflected gas atoms, in spite of the larger number of sputtered cathode atoms.

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“…Major processes that affect the ion behaviour in the cathode zone are: ionization, electric field acceleration and charge transfer. If we accept the above fact, then the space-energy distribution F i (ε, x) of ions can be roughly calculated by means of the analytical model, see [16]. According to this model, the ion energy distribution F i (ε, x) and the current average ion energy ε cav are described by…”

Section: Ion-molecule Excitationmentioning

confidence: 99%

Study of fundamental processes affecting the structure of the cathode zone of nitrogen/titanium dc discharge

Wroński

2000

J. Phys. D: Appl. Phys.

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Processes affecting the emission of the cathode zone plasma of a N 2 /Ti dc discharge were studied experimentally and theoretically. Light maxima occurring at the negative glow head (maximum II) are due to the electron-molecule excitation. Emission characteristics of this region, space distributions of lighting, dependence of the line intensity (I ) on the gas pressure (p) and current density (j d ) can be fully explained by the Monte Carlo (M-C) simulation of electron motion in this region. Emission characteristics of the space close to the cathode surface (maximum I) are complex, depending on the emitting species. Molecular lines are found to be emitted mostly due to the fast ion-N 2 interactions. The results of the analytical modelling of this process confirm the experimentally observed almost linear dependences of the intensities of these lines on the pressure and current density. Lines of atomic nitrogen are found to be due to the fast ion-N 2 interactions as well as to the fast ion-solid excitation, both accompanied by a dissociation. Particular attention was paid to the emission of sputtered material lighting in the space close to the cathode surface. This lighting results from the fast ion-sputtered atom interaction as well as from that of the sputtered atom with 'hot' atoms of the cathode surface layer. The experimentally observed dependences of the sputtered atom line intensity on the gas pressure (I ∼ 1/p) and the discharge current density (I ∼ j d × j d ) are qualitatively explained with a complex model that takes into account the analytical assessment of the energy distribution of bombarding ions, the M-C simulation of the ion-solid interaction and the M-C simulation of the motion of atoms roaming in the plasma phase. The plasma of the space close to the cathode surface (maximum I) of low-pressure discharges (∼0.1 Torr) is an effective light source for the optical emission spectroscopy of buffer gas and solid species.

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Energy distribution of heavy particles generated in the cathode fall of glow discharge

Cited by 13 publications

References 19 publications

Studies of light emission from cathode material in the plasma phase of a glow discharge

Studies of light emission from cathode material in the plasma phase of a glow discharge

Radial profile of energetic particles bombarding the substrate in a glow discharge

Study of fundamental processes affecting the structure of the cathode zone of nitrogen/titanium dc discharge

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