射频低压等离子体电子能量分布函数的探针诊断

本文对于无内电极放电的射频低压等离子体,采用探针电流调制法,设计并建立了三探针诊断电子能量分布函数的测量系统,测量了压力在10^-3—10^-1Torr下氮气等离子体的电子能量分布函数。从理论和实验上研究了探针鞘层上射频干扰电压对测量电子能量分布函数的影响,给出了确定射频干扰值以及对射频干扰的影响进行修正的方法,并采用该方法对实验数据进行了修正,得到了正确的电子能量分布函数。根据所得到的电子能量分布函数计算的电子平均能量,与由探针伏安特性计算得到的电子平均能量相差不超过5％,该结果间接证明了本文实验测量系统的可靠性以及对射频干扰影响进行修正的正确性。

PROBE DIAGNOSTICS OF THE ELECTRON ENERGY DISTRIBUTION FUNCTION IN A LOW PRESSURE RF PLASMA

A measuring system is developed for diagnostics of the electron energy distribution function (EEDF) in a electrodeless low pressure rf discharge with a triple-probe system by using the probe-current modulation method. The EEDF of a nitrogen plasma in the pressure range of 10^-3-10^-1 Torr are obtained. The effect of rf voltage penetrating the probe sheath on the determination of the EEDF is studied both theoretically and experimentally. A new approach used to estimate the value of rf voltage in the probe sheath and to calculate the actual EED from distorted distribution recorded during experiments is presented and the experimental results are corrected by using the proposed method to obtain the true EEDF. The difference between average electron energy calculated from corrected EED and that calculated from the V-I characteristics of the probe is slight, being not greater than 5%, this result seems to give indirect evidence in favor of the procedure used to determine the actual EED and the reliability of the measuring system.