平板型感应耦合等离子体源的线圈配置对功率耦合效率的影响

Effect of antenna configuration on power transfer efficiency for planar inductively coupled plasmas

基于感应耦合等离子体的变压器模型,分析了感应耦合等离子体的功率耦合效率与线圈配置(几何尺寸、电学参量)及等离子体基本参量(等离子体电子密度、电子-中性粒子有效碰撞频率)之间的关系;然后,改变平板型线圈的匝数从而改变了线圈的几何尺寸、电学参量,并且测量出了不同的线圈所对应的功率耦合效率.实验结果表明,线圈的电感量是能否实现放电的决定性因素;而功率耦合效率则与感应线圈的Q值、放电参量(气压、功率)等密切相关,射频输入功率的增加、放电气压的上升都会导致感应耦合等离子体耦合效率的提高,这与感应耦合等离子体的变压器模型预测结果是符合的.然而,变压器模型给出的提高线圈Q值可导致耦合效率增强的预测结果仅适用于同等电感量的线圈条件.本文对于单线圈的感应耦合等离子体源的研究为线圈的优化设计甚至大面积的多线圈感应耦合等离子体源研制提供了理论依据.

Based on a transformer model for inductively cowpled plasmas （ICPs）, the dependence of power coupling efficiency on Q value, plasma electron density and effective electron-atom collision frequency is analyzed. The effect of coil configuration on power coupling efficiency is studied using four types of coils （one-turn, two-turn, three-turn and four-turn planar concentric coils） experimentally. The results indicate that the inductive discharge depends on coil inductance while the coupling efficiency varies with the Q value and discharge conditions such as pressure and input power. The coupling efficiency increases with the increase of pressure and input power, which is in accordance with the transformer model. However, the prediction given in the model that an increase in coil Q value improves power coupling efficiency is only applicable for coils with the same inductance. The study on power coupling efficiency for single multi-turn coil has been applied as an experimental reference for a large-area, high density inductive discharge source using four parallel multi-turn coils.