Gamma-electron dynamics and radio frequency capacitive sheath diagnostics

Orlov, K. E.; Смирнов, А. С.

doi:10.1109/27.799811

Cited by 4 publications

(17 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2) and earlier results of Ref. [20]. This simple demonstration indicates that the shape of the RF waveform can be used to control the fine structure of the EEDF in the electron flux exiting the discharge.…”

Section: Effect Of Higher Harmonics On Evdf At the Rf Electrodesupporting

confidence: 65%

“…The latter is only true for electrons accelerated to energies higher than (Φ ), where Φ satisfies Eq. (20), that is, for electrons emitted from the RF electrode at 2π − Φ < < 2π − Φ .…”

Section: Iii2 Evdf Of Electrons Emitted From and Returning To The mentioning

confidence: 99%

“…(20), the electron exits to the RF electrode with negligible energy. Therefore, the function ( ) must have a maximum as evident in Fig.…”

Section: Iii21 Eedf Of Electrons Emitted From and Returning To Thementioning

confidence: 99%

“…Let us consider electrons with starting phases in the interval Φ < < 2 − Φ , where Φ is defined by Eq. (20). The bouncing time (in units of RF phase) for those electrons will be larger than the escape window.…”

Section: Iii22 Evdf Of Electrons Emitted From and Returning To Thementioning

confidence: 99%

See 3 more Smart Citations

Structure of the velocity distribution of sheath-accelerated secondary electrons in an asymmetric RF-dc discharge

Khrabrov

Kaganovich

Ventzek³

et al. 2015

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

Low-pressure capacitively-coupled discharges with additional DC bias applied to a separate electrode are utilized in plasma-assisted etching for semiconductor device manufacturing. Measurements of the electron velocity distribution function (EVDF) of the flux impinging on the wafer, as well as in the plasma bulk, show a thermal population and additional peaks within a broad range of energies. That range extends from the thermal level up to the value for the "ballistic" peak corresponding to the bias potential. The non-thermal electron flux has been correlated to alleviating the electron shading effect and providing etch-resistance properties to masking photoresist layers. "Middle-energy peak electrons" at energies of several hundred eV may provide an additional sustaining mechanism for the discharge. These features in the electron velocity (or energy) distribution functions are possibly caused by secondary electrons emitted from the electrodes and interacting with two high-voltage sheaths: a stationary sheath at the DC electrode and an oscillating, self-biased sheath at the powered electrode. Since at those energies the mean free path for large-angle scattering (momentum relaxation length) is comparable to, or exceeds the size of the discharge gap, these "ballistic" electrons will not be fully scattered by the background gas as they traverse the inter-electrode space. We have performed test-particle simulations where the features in the EVDF of electrons impacting the RF electrode are fully resolved at all energies. An analytical model has been developed to predict existence of peaked and step-like structures in the EVDF. These features can be explained by analyzing the kinematics of electron trajectories in the discharge gap.Step-like structures in the EVDF near the powered electrode appear due to accumulation of trapped electrons during a part of the RF cycle and their subsequent release. Trapping occurs when the RF sheath voltage exceeds the applied bias, and is decreasing. The step structures are formed by secondary electrons originating from the DC-biased surface (which also produce a peak near the energy equal to the bias potential). Additional peaks, at lower energies, are formed by the electrons emitted from the RF electrode and eventually escaping to it. The latter electrons can be grouped according to the number of bounces between the sheaths during their residence time in the discharge. Each of such groups may give rise to an individual peak in the distribution. The trap-and-release theory developed in this paper provides a convincing explanation for the observations of the ballistic and "middle energy peak" electrons measured in experiments.

show abstract

Section: Effect Of Higher Harmonics On Evdf At the Rf Electrodesupporting

confidence: 65%

Section: Iii2 Evdf Of Electrons Emitted From and Returning To The mentioning

confidence: 99%

“…(20), the electron exits to the RF electrode with negligible energy. Therefore, the function ( ) must have a maximum as evident in Fig.…”

Section: Iii21 Eedf Of Electrons Emitted From and Returning To Thementioning

confidence: 99%

Section: Iii22 Evdf Of Electrons Emitted From and Returning To Thementioning

confidence: 99%

See 2 more Smart Citations

Structure of the velocity distribution of sheath-accelerated secondary electrons in an asymmetric RF-dc discharge

Khrabrov

Kaganovich

Ventzek³

et al. 2015

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…For the smallest microplasmas discussed in this Letter, however, the mode could not be sustained and high-energy electrons can be considered to be in local equilibrium ( " 7 m L). It is also noted that contrary to what happens in low-pressure discharges [21,22], the ion flux to the electrodes (Fig. 4) and the ion density profile (not shown) are strongly time modulated both in the 100 and 75 m plasmas.…”

mentioning

confidence: 69%

Electron Kinetics in Radio-Frequency Atmospheric-Pressure Microplasmas

2007

View full text Add to dashboard Cite

The kinetic study of three radio-frequency atmospheric-pressure helium microdischarges indicates that the electron energy probability function is far from equilibrium, and three electron groups with three distinct temperatures are identified. The relative population of electrons in different energy regions is strongly time modulated and differs significantly from values recently reported from fluid analyses. It is also shown that a flux of energetic electrons (" > 5 eV) that comprises up to 50% of the total electron flux can reach the electrodes. This energetic electron flux provides a new means of delivering energy to the electrodes and tuning the surface chemistry in atmospheric-pressure discharges. The three electron groups and the engineering of an energetic electron flux might open up a new paradigm in plasma-surface chemistry that has not been considered up until now.

show abstract

Observation of a plasma-sheath resonance in a parallel-plate low-pressure rf discharge

Orlov

Смирнов

2001

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

An experimental method for the observation of a plasma-sheath resonance in a low-pressure rf capacitively coupled discharge was proposed. The method is based on secondary electron energy distribution function measurements. It was shown that the plasma-sheath resonance potential fluctuations could be observed as peaks at the secondary electron energy spectra. Depending on discharge conditions, the resonant oscillation was detected on the frequency in the range 21-30 harmonics of the driven frequency. The experimental determination of the plasma-sheath resonance frequency provides the possibility for independent measurement of the plasma density. Thus, this method can be used as a plasma density diagnostic in low-pressure capacitive discharges.

show abstract

Gamma-electron dynamics and radio frequency capacitive sheath diagnostics

Cited by 4 publications

References 14 publications

Structure of the velocity distribution of sheath-accelerated secondary electrons in an asymmetric RF-dc discharge

Structure of the velocity distribution of sheath-accelerated secondary electrons in an asymmetric RF-dc discharge

Electron Kinetics in Radio-Frequency Atmospheric-Pressure Microplasmas

Observation of a plasma-sheath resonance in a parallel-plate low-pressure rf discharge

Contact Info

Product

Resources

About