Effect of Copper Film Thickness on Stress and Strain in Grains of Different Orientation

Abstract

AbstractModels describing the effect of grain orientation on dislocation glide in a thin film are reviewed; it is predicted that differences in stress-temperature behavior should exist between grains of different orientation in a polycrystalline copper film. Direct x-ray evaluation of strains in {111} and {100| grains within primarily {111} textured copper films shows that these stresses are film thickness or grain size dependent. The {111} oriented grains behave as expected, with room temperature flow stress increasing linearly with 1/film thickness. The flow stress of grains of {100} orientation, however, is approximately constant with film thickness and is not well represented by the models. It is proposed that simplifying assumptions about orientation dependent yield may only be appropriate for the majority grain orientation population in a textured film.