The effect of nitrogen ratio on the dual-frequency capacitively coupled Ar plasma

Xiang-guo Meng, Qiang-hua Yuan

Dual RF capacitively coupled argon-nitrogen hybrid plasma is obtained by plasma enhanced chemical meteorological deposition（PECVD） equipment. The frequency of the high frequency RF source is adjustable in the range of 0 to 100 MHz, while the frequency of the low frequency RF source is fixed at 13.56 MHz. In the experiment, the frequency of HF RF source is set to 94.92 MHz. The characteristics of argon-nitrogen mixed plasma are analyzed by emission spectroscopy(OES). The electron temperature were calculated by Fermi Dirac model and the electron density were calculated by absolute measurement of continuous spectrum with different ratio nitrogen respectively. The electron temperature of argon-nitrogen mixed plasma increases with the increase of low-frequency power, The electron temperature decreases with the increase of high frequency power， The electron temperature decreases with  gas pressure increasing. When other conditions remain unchanged (power, high frequency, low frequency power, air pressure), the electron temperature increases with the increase of nitrogen content. The electron density increases with the power increase and increases with the gas pressure increase. With the increase of nitrogen content, the electron density decreases gradually.