Steady state discharge optimization in high-power impulse magnetron sputtering through the control of the magnetic field

Abstract

High-power impulse magnetron sputtering (HiPIMS) is a pulsed DC sputtering technique utilizing high power density peaks of typically more than 100 W cm−2. The discharge operation at such elevated powers can be hindered by the magnetron configuration (size and magnetic field) and/or the target conditions (e.g., material and thickness). In addition, target erosion is an important issue significantly affecting process reproducibility. In the present work, we propose a simple approach for the stabilization of the HiPIMS discharge by controlling the target magnetic field using paramagnetic spacers with different thicknesses in between the magnetron surface and the target. We demonstrate a straightforward discharge optimization, while using various target materials, such as Nb, Ta, Cr, Al, Ti, Si, and even C (graphite). The existence of a steady state high density discharge above the graphite target and the other targets in general is discussed in terms of the magnetic field configuration and the gas rarefaction effect.