不同频率驱动下容性耦合Ar等离子体随气压变化的放电特性

Discharge characteristics of capacitively coupled Ar plasmas driven by different frequencies with pressure

讨论了在驱动频率分别为13.56MHz、40.68MHz、94.92MHz和100MHz,功率为40W,气压由3.3~26.6Pa下的容性耦合Ar等离子体的放电特性。利用光谱相对强度法分别诊断了电子激发温度和电子密度。采用粒子模拟和蒙特卡罗碰撞模型(PIC/MCC),模拟了上述实验条件下中心处电子密度和电子能量概率分布(EEPF)。结果表明,在每一个驱动频率下,电子密度均随放电气压的增加而增加,而电子温度则随气压增加而降低。驱动频率为13.56MHz和40.68MHz的电子密度随气压变化趋势几乎一致,而94.92MHz和100MHz的电子温度则随气压变化趋势几乎一致。通过比较EEPF,电子温度随气压的增加有下降的趋势,与光谱诊断结果基本吻合。

The discharge characteristics of capacitatively coupled Ar plasmas driven by 13.56,40.68,94.92 and 100MHz are discussed when radio frequency power is 40W and pressure change from 3.3Pa to 26.6Pa.The electron excitation temperature and electron density were diagnosed experimentally by spectroscopic relative intensity method.Particle simulation and Monte Carlo collision model(PIC/MCC)are used to simulate the electron density and electron energy probability distribution(EEPF)under the experimental conditions.The results show that the electron density increases with the increase of pressure at each driving frequency,while the electron temperature decreases with the increase of pressure.The electron density of 13.56 and 40.68MHz has almost the same trend with the increase of pressure,while the electron temperature of 94.92 and 100MHz has almost the same trend with the increase of pressure.By comparing the EEPF,the electron temperature decreased with the increase of pressure,which was basically consistent with the spectral diagnosis results.