On the surface biasing effectiveness during reactive high-power impulse magnetron sputter deposition of zirconium dioxide

In this study, we investigate the effect of surface biasing during high-power impulse magnetron sputter deposition of non-conductive zirconium dioxide films on substrates with different capacitances. We employ reactive high-power impulse magnetron sputtering to deposit ZrO2 films using a circular Zr target in a pure oxygen atmosphere. The deposition experiments are conducted on two types of substrates: high-capacitance (thin thermally grown SiO2 on Si) and low-capacitance (soda-lime glass). By varying the time shift between the target voltage pulse and the negative substrate bias voltage pulse, we analyze the impact on the preferred crystal orientation of the deposited ZrO2 films and the deposition rate. We measure the current and voltage waveforms during the deposition process and utilize a surface charging model to understand the charging behavior of the growing film. Additionally, time- and energy-resolved ion mass spectra are measured to gain insights into the ion behavior during film growth. Our results demonstrate that energetic ion bombardment and appropriate timing of substrate biasing can influence the crystal orientation of ZrO2 films, favouring specific orientations over others. We also explain the different behavior observed on low- and high-capacitance substrates.