The discharge condition to enhance electron density of capacitively coupled plasma with multi-holed electrode

Lee, Hun Su; Lee, Yun Seong; Chang, Hong Young

doi:10.1063/1.4748576

Cited by 9 publications

(5 citation statements)

References 15 publications

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“…This mode is called the driftambipolar heating mode [32][33][34][35][36][37]. In the α-and γ-modes, electrodes with trench-like structures were found to enhance the electron heating, the ionization rate and the plasma density inside and above the structures [38][39][40][41][42][43][44][45][46][47][48]. This increase in the excitation and ionization is attributed to a hollow cathode effect and faster sheath expansion inside the structures as well as enhanced electric fields around the sharp edges of the structures [48].…”

Section: Influence Of a Phase-locked Rf Substrate Bias On The E-to H-...mentioning

confidence: 99%

Influence of a phase-locked RF substrate bias on the E- to H-mode transition in an inductively coupled plasma

Ahr

Schüngel

Schulze

et al. 2015

Plasma Sources Sci. Technol.

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The effect of a capacitive radio frequency (RF) substrate bias on the E-to H-mode transition and electron-heating dynamics in a low-pressure inductively coupled plasma (ICP) operated in hydrogen is investigated by phase-resolved optical emission spectroscopy (PROES) and Langmuir probe measurements. The inductive and capacitive power sources are driven at the same frequency and operated in a phase-locked mode with fixed but adjustable phase between them, as well as without a phase lock. For both operations, when the discharge is in the E-mode, the plasma density is significantly influenced by the choice of capacitive power. This directly affects the mode transition power: already low values of bias power can substantially reduce the threshold for the E-to H-mode transition. This coupling between both power sources is strongly dependent on the adjustable phase between them and is attributed to a phase-sensitive confinement mechanism for the highly energetic electrons produced by the expanding sheaths at the substrate and at the ICP coil. At higher pressures the beam electrons do not interact with the opposing sheath and, consequently, the effect diminishes. Using phase-unlocked operation reduces the overall beam confinement and also results in less pronounced coupling effects. In contrast, by using electrodes with ring-shaped trenches the initial energy of the beam electrons is enhanced, increasing the influence of the RF bias on the operation of the ICP discharge.

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Section: Influence Of a Phase-locked Rf Substrate Bias On The E-to H-...mentioning

confidence: 99%

Influence of a phase-locked RF substrate bias on the E- to H-mode transition in an inductively coupled plasma

Ahr

Schüngel

Schulze

et al. 2015

Plasma Sources Sci. Technol.

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show abstract

“…It has been found that RF-CCP with a hollow elec-trode can produce high-density plasma at a lower frequency (e.g., 13.56 MHz). [11,[18][19][20][21][22][23] Hollow electrode, which typically consists of hollow cylindrical electrode or rectangular electrode, is widely utilized in direct current (DC) discharge and RF discharge. [24,25] Compared with the conventional parallelplate structure, the cavity structure reduces the loss of charged particles.…”

Section: Introductionmentioning

confidence: 99%

Hollow cathode effect in radio frequency hollow electrode discharge in argon

He 贺,

He 何,

Ouyang 欧

2024

Chinese Phys. B

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Radio frequency capacitively coupled plasma sources (RF-CCPs) with hollow electrodes can increase the electron density through the hollow cathode effect (HCE), which offers a method to modify the spatial profiles of the plasma density. In this paper, the variations of the HCE within one RF period were investigated by a two-dimensional particle-in-cell/Monte-Carlo collision (PIC/MCC) model. The results show that the sheath electric field, the sheath potential drop, the sheath thickness, the radial plasma bulk width, the EEDF, and the average electron energy in the cavity vary within one RF period. During the hollow electrode sheaths expansion phase, the secondary electron heating and sheath oscillation heating in the cavity are gradually enhanced, and the frequency of the electron pendular motion in the cavity gradually increases, hence the HCE is gradually enhanced. However, during the hollow electrode sheaths collapse phase, the secondary electron heating is gradually attenuated. In addition, when interacting with the gradually collapsed hollow electrode sheaths, high-energy plasma bulk electrons in the cavity will lose some energy. Furthermore, the frequency of the electron pendular motion in the cavity gradually decreases. Therefore, during the hollow electrode sheaths collapse phase, the HCE is gradually attenuated.

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“…In addition to parallel-plate electrodes [17][18][19], hollow electrodes [20][21][22][23][24][25] are also frequently applied in RF and direct current (DC) discharges. With a hollow electrode, RF-CCPs can produce higher plasma density outside the cavity when a low frequency is utilized, which implies that plasma density enhancement effect exists in RF discharges with hollow electrodes [20][21][22][26][27][28]. Moreover, utilizing hollow electrodes with different shapes, uniform plasma density can be obtained and the film deposition quality can be improved [29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Plasma density enhancement in radio-frequency hollow electrode discharge

HE 贺,

(何锋),

(欧阳吉庭)

2024

Plasma Sci. Technol.

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The plasma density enhancement outside hollow electrodes in capacitively coupled radio-frequency (RF) discharges is investigated by a two-dimensional (2D) particle-in-cell/Monte-Carlo collision (PIC/MCC) model. Results show that the existence of plasma inside the cavity at the hollow electrode sheath fully collapsed phase is an essential condition for the plasma density enhancement outside hollow electrodes. In addition, the existence of the electron density peak at the orifice generated via the hollow cathode effect (HCE), which plays an important role in the density enhancement. It is also found that the radial plasma bulk width at the orifice affects the magnitude of the density enhancement, and narrow radial plasma bulk width at the orifice is not beneficial to obtain high-density plasma outside hollow electrodes. Higher electron density at the orifice, combined with larger radial plasma bulk width at the orifice, causes higher electron density outside hollow electrodes. The results also imply that the HCE strength inside the cavity cannot be determined by the magnitude of the electron density outside hollow electrodes.

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The discharge condition to enhance electron density of capacitively coupled plasma with multi-holed electrode

Cited by 9 publications

References 15 publications

Influence of a phase-locked RF substrate bias on the E- to H-mode transition in an inductively coupled plasma

Influence of a phase-locked RF substrate bias on the E- to H-mode transition in an inductively coupled plasma

Hollow cathode effect in radio frequency hollow electrode discharge in argon

Plasma density enhancement in radio-frequency hollow electrode discharge

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