电感耦合等离子体增强的容性耦合等离子体是一种新的等离子体源,采用这种放电方式可以获得高密度均匀的等离子体。本文主要利用朗缪尔单探针对以下几种放电方式的等离子体性质进行诊断:1双频(60,13.56 MHz)容性耦合等离子体;2电感(13.56 MHz)耦合等离子体;3电感(13.56 MHz)耦合增强的双频(60,13.56 MHz)容性耦合等离子体。通过研究电感耦合放电对容性耦合放电的影响,以及电感耦合功率、混合气体比例等宏观参量对等离子体特性的影响,获得材料处理的最佳条件。实验发现当气压是5Pa时:1双频容性耦合等离子体密度是1010 cm-3左右,极板边缘处等离子体密度较低,中心处较高。随着氩气比例增加,等离子体密度提高,电子温度降低。2电感耦合等离子体放电,随着氩气比例增加,等离子体密度增大。当氩气比例增加到70%,等离子体密度发生数量级改变,高于双频容性耦合等离子体。3电感耦合增强的双频容性耦合等离子体密度较高,当氩气比例是80%,容性电感耦合功率200 W时,组合放电等离子体密度最高,均匀性较好,电子温度升高,径向差别不大。通过实验得出,当氩气比例为80%,容性高低频功率分别为150和50 W,电感耦合功率是200 W时,双频(60,13.56 MHz)与电感(13.56 MHz)组合放电可以获得高密度均匀的等离子体。
The impact of the discharge conditions,including the discharge mode,ratio of Ar/(Ar+N2),inductively-coupled power and pressure of the inductively-coupled plasma-enhanced double-frequency-capacitive coupled plasma on the radial distributions of both ion density and electron temperature was experimentally investigated with Langmuir probe.The results show that the Ar/(Ar+N2)ratio,inductively coupled power and discharge mode significantly affect the plasma characteristics.For example,i)In double-frequency(60and 13.56 MHz)capacitively coupled plasma(DFCCP),as the ratio increased at 5Pa,the ion density(around 1010 cm-3 and with a decreasing radial distribution)increased,accompanied by a decrease of the electron temperature;ii)In the inductively coupled plasma(ICP)at 13.56 MHz,as the ratio increased to 70%,the ion density,higher than that in DFCCP,increased up to the order of 1011 cm-3,and iii)Under the discharge conditions:at a ratio of 80%and an inductively coupled power of 200 W,the ICP enhanced DFCCP outperforms both DFCCP and ICP,because of higher ion density and more uniform radial distribution of ion and electron temperature.