Wave Propagation and Plasma Production in Planar Microwave Discharges Using a Slot Antenna of Rotating Mode

Planar microwave discharges using a multi-slotted planar antenna are investigated. A three-dimensional finite difference time domain code is developed for the calculation of wave propagation in nonuniform plasmas. The enhancement of the microwave fields near the plasma resonance is revealed in accordance with the theory of the resonant absorption. The global wave electric field is obtained for various excitation modes of the antenna. By operating the antenna with transverse electric mode, where the field is rotating in the azimuthal direction, and by minimizing the reflected power from the antenna, highly uniform overdense plasmas can be produced in a wide range of gas pressures and microwave powers.