| Inductively coupled plasma source(ICPS),which is an important met hod to generate uniform and stable plasma under low pressure,has been widely used in various application fields, such as deposition andplasma etching. Due to their significant advantages of generating plasma with higher density and simpler operation, the researches on ICPSs over the past decades have attracted many researchers. Traditional methods tend to concentrate on modulating the exctied power supply and improving the structure of ICPS, thus increasing the plasma density and spacial uniformity.In order to produce plasma with high density,large volume and uniform distribution, this research developed a new type of cavity antenna-based nested double coil inductively coupled plasma source device. Due to the proliferation of plasma under the stronger collision conditions, it is still a challenge to form a larger volume of uniform plasma by a single-cavity ICPS. But the modified device enhanced by double coil in this research could achieve better results based on a series of linear and nonlinear effects as well as the coherency of ionization of the inner cavity ICPS and the outer cylinder ICPS.In this work, the impact of experimental conditions(e.g. the pressure and power) on characteristics of plasma for three different structures of ICPS are investigated. The Langmuir probe and Atomic emission spectrum are used to diagnose the key plasma parameter, including the plasma electron density, electron temperature, and spectrum. And the generation and propagtion of the plasma(E-H mode conversion, hysteresis phenomena) is discussed. The experimental results have shown that this hybrid inductively coupled plasma source device sustained by double coil present good performance in E-H mode conversion characteristics. Compared with the single coil structure, The hybrid structure could drop the threshold power trip-point of E to H Mode, thus making a wide range of H mode and more effective energy utilization( higher density and better uniformity under the same power), Besides, it is favorable to achieve more rapid and smooth mode conversion. In addition, the plasma of H mode sustained by the double coil structure has been shown to present higher density and more uniform distribution than that of the other two structures.Furthermore, the impacts of the pressure and power of applied power source on the plasma characteristics generated by the ICPS based on dual-antenna coupled structure have been researched in this paper. Some conclusions can be drawn that with the increase of discharge pressure and power, ICP accompanied by an increase in electron density. In contrast, electron temperature got a downward trend, which have good consistency with the reschearch findings about ICP properties as far as we known. Judging by the results from spectral analysis, this paper foc uses on the variation of two typical Ar Atomic spectral lines(750.4nm and 811.6nm), according to the results obtained from discipline, the high and low energy electron distribution in the discharge process was analyzed. In addition, the space-resolved experiments showed that, the plasma density located in the center of the space between the two coils is higher than both sides of the two coil. This shows that this structure can overcome skin effect obviously, made the plasma in discharge space have a better radial uniformity. |
PDF Full Text Request