Weak temperature dependence of stress relaxation in as-deposited polycrystalline gold films

Abstract

During deposition of polycrystalline gold thin films, a compressive stress develops that reversibly changes during interruptions of growth. One model for this mechanism posits that this reversible stress change is related to adatom diffusion into and out of grain boundaries and recent work has established a relationship between the reversible stress and grain size. In the current study, the dependencies of the relaxation of the compressive stress during growth interruptions on the initial stress and substrate temperature have been studied. Stress was measured in situ during growth and during interruptions in growth. The stress relaxation over a fixed time was found to be proportional to the stress when growth was terminated and the effect of temperature was found to be very weak. These results suggest that grain-boundary diffusion is not a factor in the stress relaxation.