Enhancement in ion beam current with layered-glows in a constricted dc plasma ion source

Park, Yeong-Shin; Hwang, Y. S.

doi:10.1063/1.3271252

Cited by 4 publications

(5 citation statements)

References 9 publications

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“…Applied voltages were maintained as almost constant, even when discharge currents increased up to 150 mA, showing fully developed state plasmas between the electrodes. This may be explained by a "layered-glows mode" which plays a crucial role on the relation of higher discharge currents with applied voltages only at a hollow-anode plasma source [9]. Hence, we intensively focused on plasma jets, generated by the high current mode, after voltage transition.…”

Section: Resultsmentioning

confidence: 99%

“…This is explained by the formation of stable plasma jets with a high discharge current after the voltage transition, in the section of VI characteristics. Additionally, the report [9] of experimental analyses on the plasma phenomena inside the hollow-anode discharge source to maintain the discharge at a higher sustaining current, with high efficiency in constricted DC plasmas, is a clearer rationale for improving the efficiency of sputtering processes by the developed plasma source. future works, we will conduct sputtering processes using the developed plasma source and investigate its treatment on various substrates for verification of experimental conditions once more.…”

Section: (A)mentioning

confidence: 99%

“…As a DC plasma source, it has the advantage of easy operation, low cost and high homogeneity [7]. However, analysis of plasma jets from the hollow-anode plasma is insufficient for material applications, and more practical data are needed in addition to previous research, due to the lack of measurements of plasma parameters and comparison with theory [5,6,8,9].…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Compact Hollow-Anode Discharge Source for Copper Thin Films by Sputtering Processes

et al. 2021

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A compact hollow-anode discharge (HAD) source with a size of 60 mm in radius and 70 mm in length has been developed to stably generate plasma jets for various sputtering processes in semiconductor and display fabrications. A developed HAD plasma source has been investigated by cylindrical electric probes, and the experimental results were compared to the values of numerical calculations. A uniform density discharge model with a geometry factor was proposed to estimate the profiles of plasma parameters. Owing to the difference of absolute magnitude, even with the similar trend of spatial variation, plasma parameters such as electron temperature (Te) and plasma density (ne) measured at z = 3 cm have been calibrated by the values of numerical calculations at the nozzle entrance (z = 0 cm, at the throat of the jet), and the calibration factors for Te and n0 have been deduced by comparing the experimental values to numerical calculations. These are to be explained by the decay mechanism along the axis of the jet with elastic collisions in terms of the mean free path. The developed HAD plasma source was tested for the deposition of Cu thin films with an optimized condition as a plausible application to sputtering processes.

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Section: Resultsmentioning

confidence: 99%

Section: (A)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation of Compact Hollow-Anode Discharge Source for Copper Thin Films by Sputtering Processes

et al. 2021

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“…4 It was found that the conventional DC plasma was transited to layered-glow mode, forming a striation-like plasma, with high discharge current operation. Also, operation with hydrogen gas in the layered-glow mode showed 100 times higher ion beam current compared to the operation in conventional mode.…”

Section: Introductionmentioning

confidence: 98%

Investigation of helium ion production in constricted direct current plasma ion source with layered-glows

Lee

Chung

Park³

et al. 2014

Review of Scientific Instruments

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Generation of helium ions is experimentally investigated with a constricted direct current (DC) plasma ion source operated at layered-glow mode, in which electrons could be accelerated through multiple potential structures so as to generate helium ions including He(2+) by successive ionization collisions in front of an extraction aperture. The helium discharge is sustained with the formation of a couple of stable layers and the plasma ball with high density is created near the extraction aperture at the operational pressure down to 0.6 Torr with concave cathodes. The ion beam current extracted with an extraction voltage of 5 kV is observed to be proportional to the discharge current and inversely proportional to the operating pressure, showing high current density of 130 mA/cm(2) and power density of 0.52 mA/cm(2)/W. He(2+) ions, which were predicted to be able to exist due to multiple-layer potential structure, are not observed. Simple calculation on production of He(2+) ions inside the plasma ball reveals that reduced operating pressure and increased cathode area will help to generate He(2+) ions with the layered-glow DC discharge.

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“…Constricted dc plasma ion source (or hollow anode discharge) is one example of utilizing small and dense discharges near extraction aperture. [4][5][6][7][8] A bright and small plasma ball which is attached to anode with smaller area compared to cathode is a key to make high current ion beam with high power efficiency. However, high operating pressures of 0.3-1 Torr and relatively high discharge voltages of 0.4-1 kV need to be overcome for better performance of ion source.…”

Section: Introductionmentioning

confidence: 99%

Characterization of plasma ion source utilizing anode spot with positively biased electrode for stable and high-current ion beam extraction

Park

Lee

Chung

et al. 2011

Review of Scientific Instruments

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The operating conditions of a rf plasma ion source utilizing a positively biased electrode have been investigated to develop a stably operating, high-current ion source. Ion beam characteristics such as currents and energies are measured and compared with bias currents by varying the bias voltages on the electrode immersed in the ambient rf plasma. Current-voltage curves of the bias electrode and photographs confirm that a small and dense plasma, so-called anode spot, is formed near an extraction aperture and plays a key role to enhance the performance of the plasma ion source. The ion beam currents from the anode spot are observed to be maximized at the optimum bias voltage near the knee of the characteristic current-voltage curve of the anode spot. Increased potential barrier to obstruct beam extraction is the reason for the reduction of the ion beam current in spite of the increased bias current indicating the density of the anode spot. The optimum bias voltage is measured to be lower at higher operating pressure, which is favorable for stable operation without severe sputtering damage on the electrode. The ion beam current can be further enhanced by increasing the power for the ambient plasma without increasing the bias voltage. In the same manner, noble gases with higher atomic number as a feedstock gas are preferable for extracting higher beam current more stably. Therefore, performance of the plasma ion source with a positively biased electrode can be enhanced by controlling the operating conditions of the anode spot in various manners.

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Enhancement in ion beam current with layered-glows in a constricted dc plasma ion source

Cited by 4 publications

References 9 publications

Investigation of Compact Hollow-Anode Discharge Source for Copper Thin Films by Sputtering Processes

Investigation of Compact Hollow-Anode Discharge Source for Copper Thin Films by Sputtering Processes

Investigation of helium ion production in constricted direct current plasma ion source with layered-glows

Characterization of plasma ion source utilizing anode spot with positively biased electrode for stable and high-current ion beam extraction

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