Diagnostics of Fluorine Negative Ions by Laser Photodetachment Combined with a Heated Probe in High-Density CF 4 Plasmas
Diagnostics of Fluorine Negative Ions by Laser Photodetachment Combined with a Heated Probe in High-Density CF 4 Plasmas
复制标题
高密度 CF 4 等离子体中激光光脱离结合加热探针诊断氟负离子
DOI：
10.1143/jjap.36.l1702
复制
发表时间：
1997
影响因子：
1.5
通讯作者：
K. Kadota
中科院分区：
文献类型：
--
作者：
N. Takada;D. Hayashi;K. Sasaki;K. Kadota
本文报道了螺旋波放电激发的低气压、高密度CF_4等离子体中氟负离子（F-）的绝对密度和反应动力学。采用探针辅助激光光剥离法测量F-密度。为了避免绝缘氟碳膜在探针表面上的沉积，探针尖端被加热到约1000 K。对于2 mTorr的CF 4气体压力，在等离子体密度为1.8 ×1012 cm-3的活性放电等离子体中，F-密度与电子密度的比率为n -/ne 0.06。在余辉中，电子密度迅速下降，衰减时间常数为10 µs，而F-密度在射频功率终止后约15 µs时达到峰值。在余辉中n -/ne的比率增加到~5.7。根据实验观测结果讨论了F-的产生和损失过程。
This paper reports the absolute density and reaction kinetics of fluorine negative ions (F-) in a low-pressure, high-density CF4 plasma excited by helicon-wave discharge. Probe-assisted laser photodetachment has been adopted for the measurement of the F- density. To avoid the deposition of insulated fluorocarbon films on the probe surface, the probe tip was heated to approximately 1000 K. For a CF4 gas pressure of 2 mTorr, the ratio of the F- density to the electron density was n -/n e 0.06 in the active discharge plasma with a plasma density of 1.8 ×1012 cm-3. In the afterglow, the electron density decreased rapidly with a decay time constant of 10 µs, while the F- density had a peak at ~15 µs after the termination of the rf power. The ratio n -/n e increased up to ~5.7 in the afterglow. The production and loss processes of F- are discussed based on the experimental observations.