Time-resolved imaging of a pulsed DC magnetron plasma during the sputter deposition of TiO ₂ films

Time-resolved images of the optical emissions from a pulsed DC titanium target magnetron plasma were taken with a Roper Scientific ICCD camera. The camera was exposed to the discharge for 0.05-0.2 μs with 0.05-0.2 μs separation between each exposure. At the beginning of the "on-time" when the power is turned on, the discharge initially starts preferentially in the cross corners of the race track. During the rest of the "on-time", the emissions from the straight sections of the race track of the magnetron are always slightly stronger than the emissions from the two rounded corners of the race track. This pattern extends into the start of the "off-time" when the power is turned off. The optical emissions persist for several micro-seconds into the "off-time". Argon spectral filter was used in order to record the temporal behavior of selected Ar emission lines.