Influence of microwave driver coupling design on plasma density at Testbench for Ion sources Plasma Studies, a 2.45 GHz Electron Cyclotron Resonance Plasma Reactor

Abstract

A comparative study of two microwave driver systems (preliminary and optimized) for a 2.45 GHz hydrogen Electron Cyclotron Resonance plasma generator has been conducted. The influence on plasma behavior and parameters of stationary electric field distribution in vacuum, i.e., just before breakdown, along all the microwave excitation system is analyzed. 3D simulations of resonant stationary electric field distributions, 2D simulations of external magnetic field mapping, experimental measurements of incoming and reflected power, and electron temperature and density along the plasma chamber axis have been carried out. By using these tools, an optimized set of plasma chamber and microwave coupler has been designed paying special attention to the optimization of stationary electric field value in the center of the plasma chamber. This system shows a strong stability on plasma behavior allowing a wider range of operational parameters and even sustaining low density plasma formation without external magnetic field. In addition, the optimized system shows the capability to produce values of plasma density four times higher than the preliminary as a consequence of a deeper penetration of the magnetic resonance surface in relative high electric field zone by keeping plasma stability. The increment of the amount of resonance surface embedded in the plasma under high electric field is suggested as a key factor.

Time resolved measurements of hydrogen ion energy distributions in a pulsed 2.45 GHz microwave plasma

“…We have carried out our studies of the Ion Energy Distribution Functions (IEDFs) for the main ion species in a 2.45 GHz hydrogen plasma reactor called TIPS (Test-bench for Ion source Plasma Studies). 12 The reactor is operated in the pulsed mode at 100 Hz with a duty cycle of 10% (1 ms pulse width). The measurements are conducted by using a HIDEN Plasma Ion Mass Spectrometer Model EQP 1 that uses a 45 energy sector analyzer in tandem with a quadrupole mass analyzer.…”

Breakdown transient study of plasma distributions in a 2.45 GHz hydrogen discharge

“…The experimental data were taken with a 2.45 GHz microwave plasma generator TIPS (Test-bench for Ion-source Plasma Studies) [17]. The plasma was viewed through a transparent plasma electrode composed by a 10 mm thick quartz window with two grounded tungsten meshes at both sides.…”

Langmuir probe in magnetized plasma: Study of the diffusion parameter

“…It is parallel to the reactor axis and to the probe collector. More details of the experimental set up and a scope of the reactor are given in [10]. The ion current collected by the probe at saturation is determined at large negative biased voltage ranging from -150V to -100V, when all electrons are repelled.…”