Measurement of the Degree of Dissociation in Inductively Coupled Nitrogen Discharges by Using Optical Emission Actinometry and Mass Spectrometry

Measurement of the Degree of Dissociation in Inductively Coupled Nitrogen Discharges by Using Optical Emission Actinometry and Mass Spectrometry Y. M. Shin, E. Y. Kim and T. H. Chung Department of Physics, Dong-A University, Busan 604-714 (Received 11 January 2008, in nal form 28 March 2008) The degree of dissociation is evaluated by using optical emission actinometry and mass spectrometry for inductively coupled nitrogen plasmas with pressures of 1 { 10 mTorr. The degree of dissociation is found to be between 1 % and 3.5 % and gradually increases with pressure and decreases slightly with power. The pressure dependence of the degree of dissociation measured by using optical emission actinometry and mass spectrometry exhibits a similar behavior. A physical explanation of these observations is given with a discussion of the particle balance and plasma properties, such as the electron density, the electron temperature and the electron energy probability function measured by using a Langmuir probe. PACS numbers: 52.25.Rv, 52.70.Kz, 52.20.Hv