Properties of the negative glow in an abnormal Ar-glow-discharge as derived from probe- and laser induced fluorescence measurements
A glow discharge between a Ti-cathode and a Cu-anode at a distance of 10 cm was investigated. Argon gas was used because of its technological significance. The results obtained in the abnormal discharge regime at a pressure of 0.2 mbar and a current density of 0.35 mA/cm(2) are presented. Reproducible values were measured when the O(2) and H(2) concentrations in the gas were below 1.0 E-7 mbar. Langmuir probes were used to determine the cathode fall thickness and the axial profiles of the plasma potential, of the electron density and of the electron temperature in the negative glow. An electron temperature of 1 eV was observed for about 1% of the electrons. The electric field derived from the plasma potential increased from -0.5 V/cm near the cathode fall to 0 V/cm at z = 4 cm and approached 0.3 V/cm near the anode. The results are compared with simplified theories of the negative glow. The spatial distributions of sputtered Ti atoms, of the Ti(+) ions and of the metastable Ar atoms were measured with laser induced fluorescence. Based on knowledge of the discharge parameters and the properties of the negative glow, an explanation of the observed profiles is possible.
Bibliographic Reference: Article: Proceedings of the 10th International Symposium on Plasma Chemistry, Vol. 2 (1991) 2.1-65
Record Number: 199210223 / Last updated on: 1994-12-02
Original language: en
Available languages: en