Schematic arrangement of UP-HPPMS and DC Superimposition

Schematic arrangement of a single magnetron system powered by one HiPIMS Pulse unit with one DC power supply and one DC power supply used for DC superimposition over a diode matching network.
Using a diode matching network the DC power of an additional DC power supply unit can be superimposed to HiPIMS pulses, in order to increase the deposition rate. Several experiments have shown excellent improvements of film properties using this technology. The deposition rate has proven to be more than the addition of pure HiPIMS deposition and pure DC deposition, i.e. an additional deposition portion appears. Furthermore it has turned out that the resulting properties are also a mixing of the properties of DC and HiPIMS. Therefore a tailoring of the resulting structure by proper choice of the DC and HiPIMS parameters is possible.

Schematic arragement of HPPMS and MF Superimposition

HiPIMS processes in oxide mode can suffer from instability problems due to arcing and “vanishing anode” effect. Mid-Frequency (MF) processes in contrast are mostly stable; however, HiPIMS film structure advantages can not be achieved with pure MF processes. Since MELEC GmbH pulse power supplies can be freely synchronized in bipolar (BP) or unipolar (UP) modes, a new process modification using an overlapped midfrequency (MF) and HiPIMS process was developed. This process has shown significant advantages when sputtering isolating oxides like SiO2 and Al2O3. In the case of TiO2 and ZrO2, this process works in the transition mode with feedback control, significantly improving process stability. Furthermore, by tuning the HiPIMS fraction, the plasma parameters can be tuned continuously and film properties can be optimized.

Superimposed_HPPMS_and_MF.pdf

Synchronized trigger signals of HPPMS and MF pulse waveforms and oscilloscope measurement of voltage and current