03Ba06
表面波プラズマによる電気伝導性炭素膜の高速及び大面積堆積High speed and wide area conductive carbon film deposition by surface-waveplasma
1

ベ ハンシン、 疋田 和也、鈴木 陽香、笹井 建典、豊田 浩孝
Hanshin Bae, 1Kazuya Hikita, 1,2Haruka Suzuki, 2Kensuke Sasai, 1,2,3Hirotaka Toyoda

名古屋大学工学研究科、2 低温プラズマ科学研究センター、3 核融合科学研究所
1
Department of Electronics, Nagoya univ.,
2
Center for Low-temperature Plasma Sciences, Nagoya univ., 3National Institute for Fusion Science1

1. Introduction

3. Results and Discussion

Plasma-enhenced chemical depositon (PECVD)
is widely used to deposit various types of carbonfilms from diamond-like to graphite. Graphite films
have been given attention as conductive coating
film to protect metal surface from corrosion.
However, deposition rate of the graphite film israther low (<1 nm/s)[1] and higher deposition rate
are required for its industrial application.
In this study, conductive carbon film deposition
at high deposition rate is investigated using
high-density microwave plasma, i.e., surface wave
plasma (SWP), and high negative bias voltage tothe depositing film. Film properties such as
electrical doncuctivity and hydrogen content aremeasured as a function of the bias voltage.

Electrical conductivity was measured varying thebias voltage and increase of the electricalconductivity up to ~250 -1cm-1 was observed at
higher bias voltages. Spatial uniformity of theelectrical conductivity within 20 cm was also
confirmed. Figure 1 shows H content as a functionof the bias voltage. The H content monotonicallydecreases with the bias voltage and is less than
0.4x1022 cm-3 at a bias voltage of 1.95 kV. It isknown that sp2 structure critically influences
electrical property and impingement of high energy
ions increases sp2 structure with breaking C-Hbonds.[2] The result shows reduction of C-H bonds
HydrogenContentcm-3)and suggests increaseof sp2 bondsin(1022the film.

A vacuum chamber (width 50 cm, height 26cm,depth 16 cm) is equipped with a slotted waveguideand a quartz plate, and is evacuated (<0.1 Pa) by adry pump. N-doped (100) silicon (15 cm width, 10cm height) is placed on a water-cooled stage facing
to the quartz plate. High voltage negative pulse (<2kV) is applied to the stage. Argon and benzene
gases are introduced to the vessel through mass
flow controllers at a total pressure of ~ 13 Pa. The
SWP is produced by microwave power (2.45 GHz,1.3 kW). The substrate is pre-sputtered with argon
plasma in order to remove native oxide layer of thesilicon substrate before the deposition. Carbon filmis deposited with different negative bias voltages.
Carbon film thickness (~400 nm) is measured by asurface profiler. From the film thickness anddeposition time, deposition rate was obtained andhigh deposition rate (~6 nm/s) was obtained.
Conductivity of the film is measured by fourterminal method. Hydrogen (H) content of thedeposited film is evaluated by infrared absorption
spectroscopy from C-H stretching mode absorption
at ~3000 cm-1.

Hydrogen Content (1022 cm-3)

2. Experimental Setup

4Fig. 1.

3
2
10

0

0.5
11.5
Bias Voltage VB (kV)2Bias voltage dependence of H content.

4. Summary
Using the SWP and high negative bias voltage, highconductive carbon film was successfully deposited
with high deposition rate. The conductivity increase
was promoted presumably due to the sp2 bondincrease and the H content decrease.

References[1] O‐G. Simionescu et al., Plasma Process. Polym.,
17, 1900246 (2020).
[2] P. Couderc and Y. Catherine, Thin Solid Films,
146, 93 (1987).