As a first step, decreasing the duty cycle allows a corresponding increase in power during the on-time. When a power density about two orders of magnitude higher than for conventional sputtering is maintained, a qualitative new process, termed high power impulse magnetron sputtering (HIPIMS) is observed [50,51]. Here, typical pulse lengths of 10–400 µs are used with pulse frequencies in the range of 50–500 Hz, yield a duty cycle around 0.5–5% at instantaneous power densities larger than 1 kW/cm2. At these greatly enhanced power densities, ionization of sputtered atoms occurs much more frequently than in conventional magnetron sputtering, thus increasing the fraction of
ionized sputter material and reducing the necessary amount of sputter gas .