螺旋波激发氢等离子体的电子温度及密度研究

Electron Temperature and Density of Helicon-Wave Excited Hydrogen Plasma

采用射频调谐朗缪尔单探针方法对螺旋波激发的氢等离子体I-V特性曲线进行了测量。运用Druyvestey方法对氢等离子体的电子能量分布(EEDF)及电子密度ne的变化规律进行了研究,并与发射光谱诊断结果进行了比较。结果表明:ne随着射频功率的增大成线性增大,本实验中最大值可达到1012cm-3量级,电子平均能量E随着射频功率的增大逐渐升高,并逐渐达到饱和;ne随着工作气压的增加而增大并出现峰值,存在一个最佳气压范围(2 Pa^4 Pa)使ne达到最大,E则随着工作气压的增加逐渐减小;氢气流量对ne的影响非常小,当氢气流量达到一定值(12 sccm)后,ne几乎不变化,E随着氢气流量的增加逐渐降低,最后趋于稳定;朗缪尔单探针方法与发射光谱法诊断的结果基本一致。

The characteristics, including the electron temperature and electron density, of hydrogen plasma excited by helicon-wave were studied with single RF tuned Langmuir probe. The electron energy distribution（ EED） and the plasma density, he,were also evaluated with emission spectroscopy. The results show that the RF power and the pressure strongly affect the electron density and average electron energy. For instance, as the RF power increases, ne increases linearly, peaking to 10^12 cm^-3 at a pressure of 2 Pa, and the average electron energy, E,also gradually rises up to a saturation. Moreover, as the pressure increases, the electron density ne increases, peaking at a pressure, somewhere in the range of 2 Pa - 4 Pa. Whereas E decreases. Hydrogen flow rate little affects n,, especially after the flow rate reaches 12 sccm. But as hydrogen flow rate increases, E decreases to a steady value. The Langmuir probe diagnosis agrees well with the results of the emission spectroscopy.