Pulsed DC SPUTTERING

Magnetron sputtering using pulsed DC power delivery is important for processes which are prone to arcing. Reactive sputter deposition processes – in which a metal target is sputtered in a background of reactive gas – and processes which involve sputtering of higher impedance materials – such as transparent conductive oxides – are all susceptible to arcing with a DC power delivery system.

An insulating surface at the face of the target leads to charge accumulation which will eventually be dissipated in the form of an arc. Droplets of material which are evaporated during the arc can deposit onto the substrate surface, leading to undesirable film properties and performance. Pulsed-DC power delivery is an excellent way to minimize or eliminate arcing during a reactive process.

During the pulsed-DC process, a negative bias is applied at frequencies ranging from a few to several hundred kHz; between pulses, a positive ‘reverse’ bias is applied to remove any built-up charge that has accumulated on the surface of the target. Pulsed DC magnetron sputtering is recommended for all reactive DC sputtering processes