Electrical and optical characterization of a pulsed discharge in an inverted cylindrical magnetron
Plasma Sources Science & Technology
An inverted cylindrical magnetron operating in pulsed mode was developed, with a rotating unbalanced system of magnets. The magnetic field was calculated using the finite integration technique in order to determine the optimal anode-to-cathode distance inside the reactor. A cylindrical titanium target was used for our experiments. The average power input was varied between 500 and 1300 W leading to low power densities varying between 0.9 and 2.4 W cm −2 . The frequency was fixed at a low value
... xed at a low value of 250 Hz, suitable for depositing Ti and TiO 2 at low temperatures on polymer substrates. Long on-time pulses (400 µs) were used in order to reach interesting deposition rates (>1 µm h −1 ). A transition from metallic to oxide mode was observed for all power inputs. Time-resolved optical emission spectroscopy was used for the investigation of plasma dynamics during the on-time pulse in both metallic and reactive regimes. Three phases of discharge evolution were identified in the metallic mode: the Ar-dominated phase, followed by a transition zone and a Ti-dominated phase. The emission of Ti species completely disappeared in the reactive mode, associated with the fact that titanium atoms left the target surface as TiO x molecular fragments. In conclusion, the deposition system and conditions used resulted in a new mode of TiO 2 deposition.