HiPIMS pulse shape influence on the deposition of diamond-like carbon films

Two high-power impulse magnetron sputtering (HiPIMS) systems were used to prepare hard DLC films using two types of pulse shape, one normal HiPIMS pulse and the second with short multi-pulse HiPIMS. Similar DLC film performance was achieved, however, recurring to different substrate bias values showing that the pulse characteristics are one determinant factor to the film properties. The results show that the short multi-pulse HiPIMS increases the amount of charged species reaching the substrate location. It is also confirmed that the deposited DLC films using those conditions demand lower energy (lower bias values) to achieve the same mechanical properties. The effect was related to the decrease of back attracted carbon ions occurring during the off-time between oscillations. A second effect was the presence of charged species in the target vicinity during consecutive os-cillations that aid the plasma ignition, significantly increasing the carbon ionisation and, as a result, decreasing the need for substrate bias level to obtain DLC films with a higher amount of sp3 bond hybridisation.