Measurement of ion temperature in ECR Ar/N2 plasma

The ion temperature in 2.45 GHz electron cyclotron resonance (ECR) Ar/N2 plasma was measured with a high-resolution optical emission spectroscopy. It was found that the ion temperature decreased from 0.6 to 0.03 eV as the nitrogen gas concentration was increased. It was also found that the uniformity of the electron density was improved by adding the nitrogen gas. Furthermore, the ion temperature in 915 MHz ECR plasma was measured and the similar result was obtained. In this case, the ion temperature was low compared with that in 2.45 GHz ECR plasma.