SPATIAL DISTRIBUTIONS OF ELECTRON-DENSITY AND ELECTRON-TEMPERATURE INDIRECT-CURRENT GLOW-DISCHARGE

The spatial distributions of electron temperature and density in a de glow discharge that is created by a pair of planar electrodes were stu died using double Langmuir probes. The measurement was carried out on the horizontal center plane across vertically placed circular planar p arallel plate electrodes. One electrode with magnetic enhancement (mag netron) was paired with a nonmagnetron in the two possible combination s. The measurements were carried out for the following three modes: (n onmagnetron) cathode/(nonmagnetron) anode (C-A), cathode magnetron/(no nmagnetron) anode (CM-A), and (nonmagnetron) cathode/anode magnetron ( C-AM). In the C-A mode, electrons gain energy from the imposed electri c field, and the electron temperature (T-e) rises very sharply from th e cathode to the leading edge of the negative glow where T-e reaches t he maximum. In this region, the number of electrons (N-e) is relativel y small and does not increase much. The accelerated electrons lose ene rgy by ionizing gas atoms, and T-e decreases rapidly to the plateau va lue, which is reached near the midpoint between two electrodes and ext ends to the anode. In this region, N-e increases sharply. As electrons are pulled towards the anode, a steep increase of N-e was found towar ds the anode and then N-e drops sharply very near the anode as electro ns are captured by the anode. The value of T-e increases slightly towa rds the edge of the cathode and the anode (radial position), and the m inimum T-e was found al the center. There is a clear trend that T-e an d N-e are inversely related (T-e x N-e =constant). This trend was also found in cases in which a magnetron is used as the cathode (CM-A) or as the anode (C-AM) paired with a planar nonmagnetron electrode. In th e (CM-A) mode, the magnetic entrapment of electrons is seen in the sha rp increase of N-e near the cathode surface. The characteristic toroid al glow near the magnetron cathode is associated with the N-e peak, an d the T-e peak is found inside the circular toroidal glow where N-e is small. In the (C-AM) mode, a large N-e peak was found near the anode in the center, and the T-e peak was found in the center near the catho de. A funnel shaped glow that expands from the center of the anode is distinctively different from the toroidal glow observed for the cathod e magnetron glow discharge. (C) 1996 American Vacuum Society.