Study on Monitoring of Radio Frequency Glow Discharge Plasma

提出了平行阴极和阳极之间的光学发射剖面（OEP）来监测和表征射频辉光放电等离子体，并对H_2、N_2和Ar辉光放电进行了测试。由于离子鞘和等离子体的边界恰好位于阴极鞘宽度的峰值位置，阴极鞘的宽度很容易用OEP计算出来。只有H_2放电有一个双峰，第二个峰对应于边界。用Langmuir探针法测量了等离子体参数，发现H_2和N_2等离子体的相对平均电子能Te可由离子鞘宽度is与Te is的关系来计算。等离子体密度也可以通过阴极负电位Vc和Is来估计。在实际手相处理中，研究了CCD图像传感器快速测量OEP的方法。虽然CCD技术由于难以通过光学透镜在二维图像上表示平行电极而导致OEP有所偏差，但也需要对精确的离子鞘宽度进行评估，特别是对于相对狭窄的鞘宽度。CCD图像传感器与焦距为105mm的微距透镜相结合，成功地测量了护套宽度。

Optical emission profile (OEP) between parallel cathode and anode electrodes was proposed for monitoring and characterizing radio frequency (rf) glow discharge plasma, and H_2, N_2 and Ar glow discharges were examined. The cathode sheath width was evaluated quite easily by the OEP, because the boundary of the ion sheath and the plasma lay just at a peak position in the OEP. Only H_2 discharge has a doublet peak and a second peak corresponded to the boundary. The plasma parameters are measured by the Langmuir probe method, and the relative mean electronenergy Te in H_2 and N_2 plasmas is found to be evaluated by the ion sheath width Is with a relationship Te Is. The plasma density can also be estimated by both the cathode negative potential Vc and Is.The quick measurement of the OEP using a CCD image sensor was also examined for the practical palsma processings. Although the CCD technique brought the somewhat deviated OEP because of the difficulty in the representation of the parallel electrodes at a two dimentional image through an optical lens, the precise ion sheath widths were also to be evaluated, especially for relatively narrow sheath widths. The CCD image sensor combined with a macro-lens with the focal distance of 105mm was quite successful for measuring the sheath width.