Time-Resolved Imaging of a Pulsed DC Magnetron Plasma During the Sputter Deposition of TiO$_{2}$ Films

Time resolved images 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 $\mu $s with 0.05-0.2 $\mu $s separation between each exposure. At the beginning of the \textit{on-time} when the power is turned on, the discharge initially starts preferentially in the cross corners of the \textit{race track}. During the rest of the \textit{on-time}, the emission from the straight sections of the \textit{race track} of the magnetron is always slightly stronger than the emission from the two rounded corners of the \textit{race track}. This pattern extends into the start of the \textit{off-time} when the power is turned off.~The optical emissions persist for several microseconds into the \textit{off-time}.~Spectral filters were used in order to record the temporal behavior of the emissions from various species (Ar, O). The observed ``corner effect'' at the beginning of the \textit{on time }was modeled using a Monte Carlo method by retracing the high energy electrons. Work supported by the U.S. National Science Foundation and the U.S. Army.