Characterization of the Slot Antenna Microwave Plasma Source

An annular ring slot antenna is used as the generation of large-volume 2.45-GHz microwave plasma. With argon, a surface wave at the quartz tube can be excited above 250 W. Optical emissions testify the existence of azimuthal modes of m = 4 at a pressure of 10 Pa and m = 6 at a pressure of 230 Pa. An important conclusion that the uniformity of electromagnetic field in plasma has a dependence on the value of plasma density has been acquired based on theoretical calculations under low pressures. Meanwhile, the efficiency of the plasma source is investigated experimentally. Especially, the spatial distribution of plasma parameter show that homogeneous plasma cylinder with a diameter of 160 mm has been successfully produced at the pressure of 10-1000 Pa. Index Terms--Characterization, electromagnetic field uniformity, homogeneous plasma, plasma density, surface wave mode.