Growth of multifunctional zirconium nitride thin films by reactive DC magnetron sputtering

Abstract

Zirconium nitride (ZrN) thin films have been deposited on silicon (100) substrates by reactive d.c. magnetron sputtering at various nitrogen partial pressures and different energies of ion bombardment during growth via substrate bias voltage. For optimized growth condition, the films grown with nitrogen partial pressure between 14-17% of total pressure, gave a stoichiometric composition ZrN material, which has a gold color. We found that the nitrogen partial pressure has major effects on the elemental composition of material, the deposition rate, crystal preferred orientation and color of the films. The energy of assisted-ions was varied between 8 to 108 eV. The energy of assisted-ions has slightly effects on stoichiometric composition but can help to increase the hardness and reduce the surface roughness. The ZrN (111) is a preferred orientation for all the growth conditions. The maximum hardness value of ZrN thin films is at 38.7 GPa, for the films that grown with using the energy of ions at 38 eV After annealing the films, the chemical composition of samples is just slightly changed but not the color of the films. This result indicates the good thermal stability of the ZrN thin films. The additional Zr interlayer between ZrN film and substrate does not influence to increase of the hardness. On the other hand, this layer can improve the adhesion between ZrN and substrate. This Zr interlayer may attribute to the decreasing of residual stress and prevent the film to peel off