Sputter deposition via double ring magnetrons; superior reactive and process control for high rate metal, oxide and nitride films

Abstract:
This paper demonstrates the impact of various process and plasma parameters on film growth and properties, e.g. for the growth of comparatively thick films at high rates for applications such as electrically insulation layers on technical substrates, piezoelectric films for lead-free actuators, ultrasonic transducers in MHz frequency range and energy harvesters or optical waveguides. The films were deposited by reactive magnetron sputtering via double ring magnetron with closedloop reactive gas control in the transition region. The deposition area can be up to Ø200 mm. Film properties of the sputtered films can be adjusted in a wide range by using process parameters like pulse mode ratio, reactive working point, power, rf bias and process pressure and others. The properties investigated were e. g. breakdown voltage, crystallinity, surface roughness, stress and energy generated in an energy harvesting setup. Insulation films of 30 µm thickness with breakdown voltages of around 3000 V can be sputter deposited on rough Cu substrates with deposition rates of up to 250 nm/min. Piezoelectric AlN and AlXSc1-XN films were deposited with thickness of up to 50micrometer (AlN) and 20 µm (AlXSc1-XN) for use in ultrasonic and energy harvesting applications with deposition rates of up to 200 nm/min. Coatings on Si, fused silica and metal substrates are demonstrated.