A method and apparatus for generating a plasma in a gas using a thermal source and a heat source in a common reaction zone. A process gas is flowed to a reaction zone and heated with a thermal energy source. Within the same reaction zone, a current is passed in the gas to generate a plasma within the gas. The plasma is directed to a substrate for treatment. The substrate may be a silicon wafer as part of an etching, ashing, wafer cleaning, and chemical vapor deposition.