Comparison of calorimetric plasma diagnostics in a plasma downstream reactor

The energy influx in a non-equilibrium plasma in the afterglow of a plasma downstream reactor has been measured by two different calorimetric probe types. The radio frequency discharge is investigated for oxygen (10-100%)-argon (90-0%) mixtures at relatively high gas flow rates (750-3000 sccm) and pressures (100-350 Pa). The main process parameters influencing the energy influx are the plasma power, the system pressure and the total gas flow rate. Even though the size, geometry and material composition of the used probe types are different, comparable energy flux values are achieved. Depending on the process parameters, energy fluxes between around 100 and 3500 W m-2 are found and the variation of the pressure and total gas flow rate suggests a highly flow-dependent plasma density distribution in the reactor.