Heavy particle impact excitation of atomic oxygen in front of the poweredelectrode of oxygen rf plasmas – Experiment and PIC-Simulation

摘要

The spatial (axial) and temporal (rf phase) resolved plasma induced optical emission of the atomicoxygen in an asymmetrical oxygen rf plasma (CCP) shows that the electronic excitation of oxygentakes place in two regions, in the transition region rf sheath - bulk plasma, where the excitation iscaused by collisions with electrons, and in a narrow zone directly in front of the poweredelectrode, which could not be explained with electron impact excitation. A particle-in-cellsimulation for the oxygen rf plasma confirms the electron impact excitation at the sheath edgevery well. For the excitation at the powered electrode a heavy particle impact excitation wasassumed. Collision between O2 + and the background gas O2 generate electronically excited atomicoxygen. This assumption follows in a good agreement with the experimental results.