Highly sensitive in-situ monitoring of mechanical stress during ion-beam-assisted deposition of thin titanium nitride films

Abstract

A sample holder based on the cantilever-plate technique was developed for capacitive in-situ monitoring of mechanical stress in thin films during deposition. The stress resolution is better than 0.7 MPa. Using this sample holder, thin titanium nitride films were deposited on silicon substrates by either reactive evaporation or by 2-keV ion-beam-assisted deposition at ambient temperature. The parameters deposition rate, ion to atom arrival rate and ion species were varied to investigate their influence on stress evolution. It was found that reactively evaporated titanium nitride films show a tensile stress value of about 0.5 GPa, which is nearly independent of the deposition rates used. A maximum in tensile stress is observable during the early stages of growth. This indicates the completed coverage of the substrate. The compressive stress of several GPa in films prepared by ion-beam-assisted deposition correlates well with the maximum momentum transfer for the examined parameter range.