Abstract
Nanocrystalline ZrN films were deposited on Si substrates using an unbalanced magnetron (UBM) sputtering system. The effect of bias on the microstructure and properties of zirconium nitride (ZrN) film was investigated. A negative bias voltage ranging from –20 V to –130 V was applied to the substrate. Effects of substrate bias were related to the energy and momentum of the deposited particles. Deposited energy may enhance the mobility of the adatoms to stable site on the substrate surface, but arriving ions with high energy and momentum may induce radiation damage to the growing film and produce lattice defects. Thickness (100 nm ~ 450 nm), texture, roughness, packing factor, and resistivity are correlated to the momentum and the total energy delivery with different substrate bias. Hardness of ZrN films were ranging from 20~40 GPa. The hardness increases with increasing packing factor. Nanocrystalline structures of ZrN thin film indicate that strength of hardness is due to grain boundary strength. The packing factors of ZrN films were obtained by Rutherford backscattering spectrometer (RBS), and the N/Zr ratio also can be calculated. Resistivity decreases from -20V to -90V and then increases from -90V to -130 V. Residual stress which is correlated to the momentum is ranging from -2~-13 GPa.