22P032-P
Development of line glow discharge plasma device
for preparation of DLC films
DLC 成膜に向けた大気圧線状グロー放電プラズマ装置の開発
Keita Fukui, Masanori Miyamae, Yusuke Kikuchi, Yoshiaki Matsuo
Yasumitsu Horiguchi*, Yoshimi Nishimura*, Masayoshi Nagata, Mitsuyasu Yatsuzuka
福井 経太，宮前 公準，菊池 祐介, 松尾 吉晃, 堀口 恭光*，西村 芳実*，
永田 正義，八束 充保
Graduate School of Engineering, University of Hyogo
2167 Shosha, Himeji, Hyogo 671-2280, Japan
兵庫県立大学 工学研究科 〒671-2280 兵庫県姫路市書写2167*Kurita Seisakusyo Co. Ltd.
Ujitawara, Kyoto, 610-0221, Japan*（株）栗田製作所 〒610-0221 京都府綴喜郡宇治田原町
Line glow discharge plasmas (LGDPs) at atmospheric pressure were generated for preparation of large-area
amorphous carbon films using a mixed gas of He as a carrier gas and CH4 as a precursor. The dielectricbarrier discharge was produced by the high-voltage, high-repetition bipolar pulse applied between theparallel-plate electrodes with two quartz glasses as dielectric barrier. The LGDP with a length ofapproximately 170 mm was extracted on the stainless-steel substrate by applying pulsed bias-voltage to thesubstrate. An amorphous carbon film with the same length as the LGDP was synthesized by the LGDP at
atmospheric pressure

1. Introduction
Diamond-like carbon (DLC) films havephysical and chemical properties for applications
such as high mechanical hardness, low friction,
chemical inertness, electrical insulation, opticaltransparency, and biological compatibility [1]. DLC
films can be produced by utilizing different kinds ofdischarge plasmas at low pressure, resulting in low
deposition rates, typically, at most 0.05 µm/min [2]and also the requirement of costly vacuum systems.
Atmospheric pressure glow discharges areattractive for various material processing because of
rapid deposition rate due to the use of high-density
plasma and the cost reduction by removing theassociated vacuum system. The deposition of DLC
films at atmospheric pressure has been achieved bynanopulse plasma [3], dielectric barrier discharge(DBD) [4] and the torch-type plasma [5]. For
preparation of large-area amorphous carbon film,
the line glow discharge plasma (LGDP) wasproduced with a high-voltage, high-repetition
bipolarpulseusingthethree-electrodeconfiguration [6]. In this experiment, a high-voltage
pulse source was used for production of DBD
plasma and also LGDP, so that the stability andcurrent density of LGDP was controlled.
In this paper, we study on the stable generationof LGDP using two independent high-repetition
bipolar pulses which are synchronized each otherfor production of DBD and LGDP, respectively.

Fig. 1 Experimental setup

The first result of the preparation of amorphous
carbon film is shown.
2. Experimental setup
Figure 1 shows a schematic of experimental
setup for carbon film deposition by the LGDP atatmospheric pressure, where the parallel-plateelectrode (upper) and a cross-sectional view of theFig. 2 Magnitude of the optical emission from theplasma as a function of the phase delay.

three-electrode configuration and electrical circuit(lower). The DBD source plasma was generated bya high-voltage, high-repetition bipolar pulse with afast rise time using the parallel-plate geometry witha gap width of 2 mm. Two quartz glasses with thethickness of 5 mm and the width of 250 mm x 150mm were placed between two electrodes made ofstainless-steel (170 mm x 150 mm) to produce
DBD. A mixed gas of He as a carrier gas and CH4
as a precursor was supplied to the discharge region
from the upper side of the parallel-plate electrodes.
Applying another pulsed bias voltage to the gap
between the parallel plate electrode and the bias
electrode (stainless-steel substrate), the LGDP wasextracted on the substrate for a film deposition. The
pulsed bias voltage and bias current were measured
with a high-voltage probe and a pulse CT,respectively. The light emission from the extracted
plasma was observed by a photomultiplier tube
(Hamamatsu Photonics, R960)
3. Experimental results
There is little diffused plasma on the substratefrom the DBD without pulsed bias voltage. Whenthe pulsed bias voltage was applied to the substrate,
the uniform LGDP was observed in the gap
between the parallel-plate electrode and thesubstrate. It is found in Fig. 2 that as the bias
voltage is applied at several µs later, the bias
current and optical intensity of LGDP become themaximum. As not shown here, when the voltage
was increased, both intensities of bias current andoptical emission were enhanced. Further increase inbias voltage led to the streamer discharge from theglow discharge.
Figure 3 shows the result of amorphous carbon
film on the substrate prepared by the LGDP. Here, ahalf-cylinder substrate of stain-less steel (SUS304)
is used, and the gap length between the parallel
plated electrode and the substrate is 1 mm. It is
confirmed that the width of 2 mm of the film issuccessfully prepared. Thus, amorphous carbon
film with large area could be prepared by rotating acylindrical substrate. The detail properties of the
prepared film such as thickness, hardness, andRaman spectrum will be investigated.
4. Summary
The uniform LGDP at atmospheric pressure wasgenerated by two independent high-voltage,high-repetition
bipolarpulsesusing
thethree-electrode configuration. When the pulsed bias
voltage was applied to the substrate at several µs
later, the largest intensity of LGDP was observed.
The amorphous carbon film was successfully
prepared by the LGDP.
Acknowledgments
This work has been supported by A-STEP
program from Japan science and technology
agency.
References[1] J. Robertson, Surf. Coat. Technol, 50 (1992) 185.
[2] Y. Oka, Y. Nishimura and M. Yatsuzuka, Vacuum 73(2004) 541.
[3] Y. Kondo, T. Saito, T. Terazawa, M. Saito, and N.
Ohtake, Jpn. J. Appl. Phys 44 (2005) L1573.
[4] W.J. Liu, X.J. Guo, C.L. Chang, and J.H. Lu, Thin
Solid Films 517 (2009) 4229.
[5] Y. Matsuo, Y. Horiguchi, Y.Nishimura, and M.
Yatsuzuka, Advanced in Appl. Plasma Sci. 7 (2009)251.
[6] Y. Kikuchi, Y. Matsuo, Y. Horiguchi, Y. Nishimura,M. Nagata, and M. Yatsuzuka, Frontier of Appl.
Plasma Technol. 3 (2010) 65.

170 mm38 mm
2 mm
Amorphous carbon film
Fig. 3 Amorphous carbon film on the substrate prepared by the LGDP.