Modeling of the plasma heating in unmagnetized low pressure microwave discharges

Summary form only given. Low pressure microwave plasma sources used for materials processing generally operate as overdense plasmas with the plasma density greater than the critical density. These sources can be operated with a static magnetic field that provides for ECR heating or without a static magnetic field via ohmic, resonance and other non-ohmic and stochastic heating mechanisms. Even when ECR strength magnetic fields are present these other heating mechanism that occur in unmagnetized plasmas can be important and may even dominate. This paper examines via a two-dimensional self-consistent microwave field and plasma model the heating of low pressure, overdense, unmagnetized plasma discharges. Further the models are constructed to closely match an experimental system that has been extensively characterized. This experimental system is a 2.45 GHz resonant cavity plasma source that has been studied while running argon discharges at pressures of 4-60 mTorr using Langmuir probes to determine the plasma density and electron temperature and using microwave field probes to measure the microwave field strength.