Expanding Plasma Region of an Inductively Driven Hydrogen Discharge

Kiss’ovski, Zh; Kolev, St; Shivarova, A.; Tsankov, Tsanko Vaskov

doi:10.1109/tps.2007.901938

Cited by 11 publications

(17 citation statements)

References 43 publications

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“…Its dependence on the pressure is non-monotonous (figure 5), with a formation of a maximum at (1-3) Pa. The decrease of at the high pressures is in agreement with the results obtained away from the driver (z = 12 cm as here) in earlier experiments [7,11] hydrogen. Despite of the -increase in the driver with the gas pressure, the electron density in the expanding plasma volume decreases due to lowering of the transport coefficients.…”

Section: Resultssupporting

confidence: 90%

“…The tandem type plasma source studied here driven by an inductive discharge at 27 MHz has been extensively investigated [7][8][9][10][11], both in argon and hydrogen, in view of applications in plasma technologies and as a negative ion source. The plasma produced in the driver region of the source expands in a larger second chamber.…”

Section: E Nmentioning

confidence: 99%

“…The experimental set-up (figure 1) is a tandem type plasma source (see [11] for more details). In brief, a 9-turn coil inductively couples the HF power (at 27 MHz) to the discharge produced in a quartz tube (4.5 cm in diameter and 30 cm in length).…”

Section: Experimental Set-upmentioning

confidence: 99%

See 2 more Smart Citations

Laser photodetachment diagnostics of electronegative expanding plasmas

Kiss’ovski

Kolev

Shivarova

et al. 2008

J. Phys.: Conf. Ser.

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The study presents results from measurements of the negative hydrogen ion density by laser photo-detachment in the expanding plasma region of an inductively-driven tandem plasma source. The results obtained show that the negative ion density and the plasma electronegativity increase with increasing the high-frequency power absorbed in the discharge. An optimum gas pressure range [(1-3) Pa] for negative ion production in the expansion chamber is observed.

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Section: Resultssupporting

confidence: 90%

Section: E Nmentioning

confidence: 99%

See 1 more Smart Citation

Laser photodetachment diagnostics of electronegative expanding plasmas

Kiss’ovski

Kolev

Shivarova

et al. 2008

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

show abstract

“…towards the large volume expansion region, the fast drop in the plasma parameters formed at the edge of the power input region transfers into smoother variations at the beginning of the second chamber, on the other side of the driver, towards z → −30 cm, the strong gradients of the plasma parameters stay the same over the whole distance to the back wall of the small diameter vessel. As pointed out in [22], the experiments also show a stronger drop in the plasma parameters-compared with that in a larger volume expanding plasma vessel-when the size of the expanding plasma vessel is the same as that of the driver.…”

Section: Spatial Distribution Of the Plasma Parameterssupporting

confidence: 60%

Two-dimensional fluid model of a two-chamber plasma source

Kolev

Shivarova

Tarnev

et al. 2008

Plasma Sources Sci. Technol.

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This study presents a two-dimensional fluid-plasma model developed for describing the cw regime operation of a tandem plasma source, consisting of a driver and an expansion plasma volume of different sizes. The moderate pressure range considered (tens to hundreds of milliTorr) allows a description within the drift-diffusion approximation, as employed in the model. Argon discharges maintained in a metal gas-discharge vessel are treated. The discussions stress charged-particle and electron-energy fluxes as well as the spatial distribution of their components. The main conclusions are for (i) different electron and ion fluxes resulting in a net current in the discharge; (ii) a radial ion flux prevailing over the axial one and an axial electron flux prevailing over the radial one; (iii) ion motion determined by the dc electric field and drift-diffusion electron motion influenced by thermal diffusion; (iv) plasma maintenance in the expansion plasma chamber due to charged-particle and electron-energy fluxes from the driver; (v) importance of the convective flux in the electron-energy balance; (vi) electron-energy losses for sustaining the dc electric field in the expansion plasma volume strongly predominating over the losses through collisions and (vii) electron cooling accompanied by a strong drop in the plasma density and in the potential of the dc electric field, due to the plasma expansion in a bigger volume. In general, the results show that the gas pressure range usually considered to be governed by ambipolar diffusion shows up in a different regime: a regime with a dc current, when the discharge is in a metal chamber with different dimensions in the transverse and longitudinal directions.

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“…The n o (and therefore Γ i ) has been reported to increase in a remote ICP system with a planar/spiral coil configuration when P ICP is kept constant and the pressure is raised [44,59]. However, the spatial properties of plasma parameters in remote downstream ICP systems with an upper source chamber driven by a cylindrical coil configuration and a lower expansion chamber near the substrate can be quite complicated [24,[62][63][64][65]. The substrate table, and hence the location at which RFEA measurements were conducted, lies at the end of the expansion chamber where n o has been reported to decrease with pressure for a constant P ICP [38,62,63].…”

Section: Reactive Plasmas For Peald Without and With Rf Substrate Biasingmentioning

confidence: 99%

Energetic ions during plasma-enhanced atomic layer deposition and their role in tailoring material properties

Faraz

Arts

Karwal

et al. 2019

Plasma Sources Sci. Technol.

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Plasma-enhanced atomic layer deposition (PEALD) has obtained a prominent position in the synthesis of nanoscale films with precise growth control. Apart from the well-established contribution of highly reactive neutral radicals towards film growth in PEALD, the ions generated by the plasma can also play a significant role. In this work, we report on the measurements of ion energy and flux characteristics on grounded and biased substrates during plasma exposure to investigate their role in tailoring material properties. Insights from such measurements are essential toward understanding how a given PEALD process at different operating conditions can be influenced by energetic ions. Ion flux-energy distribution functions (IFEDFs) of reactive plasmas typically used for PEALD (O 2 , H 2 , N 2 ) were measured in a commercial 200 mm remote inductively coupled plasma ALD system equipped with RF substrate biasing. IFEDFs were obtained using a gridded retarding field energy analyzer and the effect of varying ICP power, pressure and bias conditions on the ion energy and flux characteristics of the three reactive plasmas were investigated. The properties of three material examples-TiO x , HfN x and SiN x -deposited using these plasmas were investigated on the basis of the energy and flux parameters derived from IFEDFs. Material properties were analyzed in terms of the total ion energy dose delivered to a growing film in every ALD cycle, which is a product of the mean ion energy, total ion flux and plasma exposure time. The properties responded differently to the ion energy dose depending on whether it was controlled with RF substrate biasing where ion energy was enhanced, or without any biasing where plasma exposure time was increased. This indicated that material properties were influenced by whether or not ion energies exceeded energy barriers related to physical atom displacement or activation of ion-induced chemical reactions during PEALD. Furthermore, once ion energies were enhanced beyond these threshold barriers with RF substrate biasing, material properties became a function of both the enhanced ion energy and the duration for which the ion energy was enhanced during plasma exposure. These results have led to a better insight into the relation between energetic ions and the ensuing material properties, e.g. by providing energy maps of material properties in terms of the ion energy dose during PEALD. It serves to demonstrate how the measurement and control of ion energy and flux characteristics during PEALD can provide a platform for synthesizing nanoscale films with the desired material properties.

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Expanding Plasma Region of an Inductively Driven Hydrogen Discharge

Cited by 11 publications

References 43 publications

Laser photodetachment diagnostics of electronegative expanding plasmas

Laser photodetachment diagnostics of electronegative expanding plasmas

Two-dimensional fluid model of a two-chamber plasma source

Energetic ions during plasma-enhanced atomic layer deposition and their role in tailoring material properties

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