Production of low-electron-temperature electron cyclotron resonance plasma with large area using 915 MHz microwave

The effect of microwave discharge frequency of 915 MHz on the electron temperature and the plasma uniformity in electron cyclotron resonance (ECR) plasma was studied by measuring the plasma parameters under various experimental conditions. It was found that the electron temperature of 915 MHz ECR plasma could be reduced to 1.3 eV, which is lower than that of conventional 2.45 GHz ECR plasma by 2-3 eV. The radial uniformity of 915 MHz ECR plasma is high, and can be further improved by optimizing the external parameters.