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Atmospheric Pressure Plasmas: Low-Temperature Processes
ByHiroaki Kakiuchi, Hiromasa Ohmi, Kiyoshi Yasutake
Pages 10

Of late, there has been a considerable interest in the efficient deposition process of functional thin films at low temperatures. Nonthermal plasmas generated under atmospheric pressure (AP) are potential candidates to achieve it, since AP plasma can serve as an efficient source of atomic and molecular active species. Numbers of academic and industrial research groups have reported the preparation of thin films mainly with regards to polymers, inorganic silicon oxides, and carbon materials using various types of AP plasma sources, such as corona, dielectric barrier, and AP glow discharges, that can produce a nonequilibrium AP plasma. However, from the viewpoint of depositing uniform thin films, radio-frequency (RF) and very-high-frequency (VHF) excitations of AP plasma that are capable of avoiding unstable streamers and filamentary discharges are promising. In this entry, we first comment on the key concepts of using AP plasma in the deposition process of good-quality functional thin films. We then describe the details of the three types of electrode systems we have developed to effectively use AP-VHF plasma for the deposition of silicon (Si) and related materials. Finally, we summarize the experimental results on the deposition of Si in both crystalline and amorphous phases, silicon nitride, and silicon oxide films using the AP-VHF plasma.