Effects of showerhead hole structure on the deposition of hydrogenated microcrystalline silicon thin films by vhf PECVD

Wi, Sung-Suk; Lee, Hojun; Kim, Daeil; Hwang, D. M.; Chang, Woo Sok

doi:10.1116/1.4721287

Cited by 11 publications

(6 citation statements)

References 20 publications

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“…The design of the showerhead is crucial as it directly affects the distribution of the flow field . By optimizing the structure of the showerhead, it is possible to control the deposition shape of the film and improve the uniformity of the film thickness. − When the shape of the microchannel on the showerhead changes, the deposition rate also changes simultaneously . Therefore, the structure of the microchannel directly affects the gas uniformity of the showerhead.…”

Section: Introductionmentioning

confidence: 99%

RETRACTED: Effect of Fluoride Layer Growth on the Deposition Rate under Different Microchannel Structures

Liu,

Yue,

Lin

2023

ACS Omega

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In the plasma-enhanced chemical vapor deposition (PECVD) process, a showerhead is used to enhance fluid uniformity in the chamber. The uniformity of the flow field will be affected by changing the microchannel on the showerhead, which in turn directly affects the uniformity of deposition. The showerhead will be etched during the cleaning process due to the presence of HF, which will form a fluoride layer. This layer will cause a decrease in the diameter of the microchannels, resulting in changes in the deposition uniformity. The impact of diameter changes can be reduced by making modifications to the microchannel structure. By adopting a coupling of the Navier−Stokes and Direct Simulation Monte Carlo (NS-DSMC) methods, we obtained the velocity variation of two typical microchannels (equal-diameter type and expansion type) under the same diameter change. The results indicate that compared to the equal-diameter type, the expansion type exhibits a smaller change in velocity for the same change in diameter. For the surface reaction limited regime, a stable velocity leads to a consistent residence time, which is advantageous for maintaining the uniformity of the film thickness. Therefore, compared to the equal-diameter type microchannel, the expansion type can reduce the impact of changes in diameter.

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Section: Introductionmentioning

confidence: 99%

RETRACTED: Effect of Fluoride Layer Growth on the Deposition Rate under Different Microchannel Structures

Liu,

Yue,

Lin

2023

ACS Omega

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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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“…41 The effect of a showerhead hole structure on the deposition of hydrogenated microcrystalline silicon thin films was investigated. 48 Such structured electrodes can overcome the problem of low and non-uniform plasma densities in low frequency CCPs and might provide the basis to realize advanced plasma applications at low frequencies around 13.56 MHz to avoid parasitic electromagnetic effects at higher driving frequencies. Grooved electrodes have also been found to have an active influence on the collection of dust particles as well as their trapping behavior and movement in such plasmas.…”

Section: Physics Of Plasmas 23 033510 (2016)mentioning

confidence: 99%

“…In order to enhance the plasma density and improve its lateral uniformity at the conventional frequency of 13.56 MHz, the use of structured electrodes has been proposed based on different trench shapes. 12,17,[39][40][41][42][43][44][45][46][47][48][49][50] A grooved target has been used in dc magnetrons to realize high discharge currents at very low pressures of a) Email: ohtsuy@cc.saga-u.ac.jp 1070-664X/2016/23(3)/033510/7/$30.00…”

Section: Introductionmentioning

confidence: 99%

Capacitive radio frequency discharges with a single ring-shaped narrow trench of various depths to enhance the plasma density and lateral uniformity

et al. 2016

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Spatial structures of the electron density and temperature in ring-shaped hollow cathode capacitive rf plasma with a single narrow trench of 2 mm width have been investigated at various trench depths of D ¼ 5, 8, 10, 12, and 15 mm. It is found that the plasma density is increased in the presence of the trench and that the radial profile of the plasma density has a peak around the narrow hollow trench near the cathode. The density becomes uniform further away from the cathode at all trench depths, whereas the electron temperature distribution remains almost uniform. The measured radial profiles of the plasma density are in good agreement with a theoretical diffusion model for all the trench depths, which explains the local density increase by a local enhancement of the electron heating. Under the conditions investigated, the trench of 10 mm depth is found to result in the highest plasma density at various axial and radial positions. The results show that the radial uniformity of the plasma density at various axial positions can be improved by using structured electrodes of distinct depths rather than planar electrodes. V

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Effects of showerhead hole structure on the deposition of hydrogenated microcrystalline silicon thin films by vhf PECVD

Cited by 11 publications

References 20 publications

RETRACTED: Effect of Fluoride Layer Growth on the Deposition Rate under Different Microchannel Structures

RETRACTED: Effect of Fluoride Layer Growth on the Deposition Rate under Different Microchannel Structures

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

Capacitive radio frequency discharges with a single ring-shaped narrow trench of various depths to enhance the plasma density and lateral uniformity

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