High Power Impulse Magnetron Sputtering

High power impulse magnetron sputtering (HiPIMS) plasmas produce a very energetic growth flux for the synthesis of thin films with superior properties. High power densities in the range of a few kW/cm^2 are applied to a metal target electrode in short pulses with a length of 10 to 400 µs and duty cycles of a few percent or less in an argon plasma gas. Fast camera and probe measurements revealed the formation of very characteristic plasma patterns that become visible as rotating localized ionization zones, so called spokes. The appearance of these spokes at high plasma powers is believed to be essential for the good performance of HiPIMS plasmas. The rotation direction of the spokes is in ExB direction at high plasma powers, but in retrograde ExB direction at low plasma powers.