Direct current (DC) sputtering is a thin film deposition technique that uses ionised gas molecules to vaporise (sputter) molecules off the target material into plasma. DC sputtering is the preferred technique for electrically conductive target materials because of its low cost and high level of control. The DC magnetron sputtering process involves a vacuum chamber containing the target material parallel to the target substrate. The vacuum chamber contains a high purity inert gas such as argon that becomes charged when exposed to a pulsed DC current. The metal target material acts as the negative node (cathode) while the substrate acts as the positive pole (anode). A DC current passes through the system, which causes the argon gas to ionise and results in a forceful collision of the ions with the negatively-charged source metal. These collisions knock off metal ions off the surface of the target into the plasma (a mixture of ionised gas ions and electrons). The positively-charged substrate attracts the negatively-charged plasma, which condenses on the surface of the substrate, forming a thin film coating of the neutral source.