Numerical simulation of evolution features of the atmospheric-pressure CF₄ plasma generated by the pulsed dielectric barrier discharge

Abstract

The atmospheric-pressure CF₄ plasma has the high application potential in the field of semiconductor fabrication since it can combine the excellent capability for the CF₄ plasma etching with the easy atmospheric-pressure operation. In this work, the fluid model has been carried out to numerically research evolution features of the atmospheric-pressure CF₄ plasma generated by the pulsed dielectric barrier discharge. The computational results show that the averaged electron temperature dramatically increases during the rising and the falling phases of the applied voltage pulse, and then swiftly decreases. The discharge current density has the waveform of two bipolar short pulses. The electrons and CF₃ ⁺ ions form the cathode sheath at the discharge duration. However, the CF₃ ^- and F⁻ negative ions take the place of the electrons to sustain the cathode sheath of the CF₄ discharge plasma at the time interval between the two bipolar discharge pulses. During the time interval of the two adjacent applied voltage pulses the discharge region is the quasi-neutral plasma region, and meanwhile CF₂ ⁺ and CF₃ ^- are the dominated charged species. Moreover, F and CF₃ maintain the relatively stable high densities and uniform axial distributions during the whole period of the applied voltage.

Graphical abstract