三频容性耦合氮等离子体中N_(2)和N_(2)^(+)的转动温度和振动温度试验

Experiment on rotational and vibrational temperatures of N_(2)and N_(2)^(+) in triple-frequency capacitively coupled nitrogen plasma

通过光谱拟合方法研究三频容性耦合氮等离子体中高频(high frequency,HF)、中频(intermediate frequency,IF)和低频(low frequency,LF)功率对氮分子(N_(2))和氮分子离子(N_(2)^(+))的转动温度(T_(r))与振动温度(T v)的影响。试验结果表明:由于等离子体的粒子密度升高,导致粒子间碰撞加剧且温度升高;N_(2)和N_(2)^(+)的T_(v)随HF功率的增加而上升的趋势非常明显,而随IF或LF功率的增加则基本不变或略有下降。由此可知,HF功率对N_(2)和N_(2)^(+)的T r影响最大,即对等离子体的加热最为明显,而LF功率的增加对等离子体的加热作用较小,IF居于两者之间。因此,HF功率有利于提高N_(2)和N_(2)^(+)的化学活性并有利于其分解,而IF和LF功率影响不大,甚至能一定程度上降低N_(2)和N_(2)^(+)的化学活性。

The effects of high,intermediate and low frequency power on the rotational and vibrational temperatures of nitrogen molecule(N_(2))and nitrogen molecule ion(N_(2)^(+))in a triple-frequency capacitively coupled nitrogen plasma were studied by spectral fitting.The results show that the plasma density is higher with high frequency power,and then the collision intensifies,resulting in the temperature rise.The vibrational temperature of N_(2)and N_(2)^(+)increases with high frequency power,but remains unchanged or decreases slightly with the intermediate or low frequency power.Therefore the plasma heating is most obvious due to the high frequency power,while the plasma heating effect is less due to the increase of the low frequency power,and the intermediate frequency power is between the two.This indicates that the high frequency power is also beneficial to the improvement of the chemical activity of N_(2)and N^(2+)and its decomposition,while the intermediate and low frequency power has little effect or even a certain extent to reduce the chemical activity of N_(2)and N_(2)^(+).