We generated and diagnosed a large-area planar surface wave nitrogen plasma excited by a slotted antenna applicator, which has four slots with an inclination angle of 75° with respect to the wall centerline. When the 2.45 GHz microwave power applied was larger than 500 W, a stable nitrogen plasma was generated as a large-area surface wave discharge. We carried out the optical emission spectroscopy measurement of the generated plasma and observed the intensity of the second positive system of nitrogen molecules. It was found that the vibrational temperature of the C state of nitrogen molecules is about 0.67–0.86 eV at the discharge pressures of 0.3–1.0 Torr and decreases with discharge pressure. The rotational temperature was found to be 0.13–0.14 eV, which is almost independent of discharge pressure. Probe measurement showed that the electron temperature and density are about 2.0–4.0 eV and in the order of 1011 cm-3, respectively. When the microwave power was as low as 400 W, a transition to a volume wave-excited plasma was observed, in which the electron density is less than the critical density for the 2.45 GHz microwave.
各種検索
サポート
ヘルプ