Numerical Simulation Of Large-Scale Rectangular Surface-Wave Plasma Source

Surface wave plasma(SWP) is produced and sustained by the electric field of surfacewave propagating along the dielectric-plasma interface. With the rapid development ofultra-large-scale integrated(ULSI) devices, solar cells, flat panel displayer,microelectromechanical systems ere, SWP source, as a potential large-scale plasmaprocessing tool, has received unprecedented attention since the 90's of last century.Compared with conventional plasma source, SWP source has many advantages such asfree from the use of electrodes and external magnet field, permits the generation oflarge-scale high-density and uniform plasmas. Due to the complex coupling mechanismsbetween antenna array, surface wave and plasma in the SWP source, it urgently needscomputer numerical simulation to study relevant physical problems and as well as tooptimize the design of the device.The large-scale rectangular SWP source is the research object of numerical simulationin this dissertation. The main works are described as follows:1. The propagation of surface wave excited by arbitrary slot antenna is simulated bythe finite difference time domain(FDTD) method combined with the Maxwell's equationsand the cold plasma model. The dependences of surface wave propagation on variousfactors such as plasma density, electron collision frequency, quartz thickness, quartzpermittivity, and the air gap below antenna are investigated separately. The results showthat surface waves excited by different antennas have the nature of linear superposition,and the mode is inconsistent with eigen mode because of the influence of antennas. Thickquartz and the existence of air gap are not conducive to the excitation of surface wave.When the permittivity of dielectric is around 3.7, the antenna can excite more intensivesurface wave.2. The distributions of electromagnetic fields, electron density and temperature whendevice working at uniform and stable states are simulated based on two assumptions:plasma is uniform distributed in the chamber and deposited power is uniform distributedin horizontal plane. The influences of different antenna arrays on the electromagneticfields in the waveguide, the propagation of surface wave and the microwave depositedpower are analyzed. It is found that when plasma density is at around 1.0×10¹⁸m^-3, thereflection rate of microwave power can be lower than 20%. The more compact andintensive the surface wave is, the less reflection rate would be. At around 2-4 cm from the quartz there appears a peak of electron density and the peak position moves towards thequartz as the increase of gas pressure. When the gas pressure increases to a certain value,plasma density will saturate.3. The spontaneous outspread of plasma under the "push" of surface wave issimulated using a quasi-steady-state time-stepping model. Self-consistent generatedelectron density and temperature spatial distributions are presented. The impacts ofdifferent antenna arrays, microwave input power, gas pressure, air gap on the spontaneousoutspread of plasma are analyzed. The viewpoint that producing large-scale SWP bytraveling surface wave rather than standing surface wave is proposed.4. Microwave resonant absorption is studied using the particle-in-cell plus MonteCarlo collision(PIC+MCC) method. Simulated local resonant width and Spatial andtemporal distribution of resonant electric field are in coincidence with theoreticalcalculations. The resonance occurred in SWP source must be not more than 0.1 mm wideaccording to the simulation results, and resonant point moves towards quartz as gaspressure increases. Surface wave propagations under different electron temperature aresimulated using two-dimensional PIC method, the modes are identical to the resultobtained by the fluid based cold plasma model.