Effect of wet and dry nebulizer gas on the spatial distribution of electron density

Spatially resolved, radial electron density ( n e ) profiles were measured at rf power settings of 1.25 and 1.75 kW and vertical heights of 4, 8, 12, 16 and 20 mm above the load coil with and without water vapor in the nebulizer gas. The removal of water vapor from the aerosol gas resulted in a decrease in electron density. The greatest change in n e , a decrease of 1.0 × 10 15 cm −3 , was observed at 4 mm above the load coil in the annular region. The differences in electron density became smaller with increasing height above the load coil. Electron density was also measured with no aerosol gas flow into the plasma. Electron density significantly increased when aerosol gas was eliminated.