An X-ray diffraction profile analysis of vacuum-evaporated copper films: normal and oblique vapour incidence

Abstract

A detailed study of copper films was made in the thickness range 80-330 nm for the 111, 200, 220, 311 and 222 reflections. Only high concentrations of growth-twin stacking faults have been observed. The line-shift analysis has shown the existence of small lattice parameter changes and appreciable residual stresses, tensile in nature, for the films deposited from an oblique vapour beam. The line-broadening analyses considering multiple-order and single-order ('linlog') reflections have shown the presence of small coherent domain sizes lying in the range 45-175 AA and an appreciable amount of total RMS strain resulting in a density of dislocations rho approximately 1011 cm-3. The effective coherent domain size De and RMS strain values obtained from the 'linlog' method show considerable anisotropy and the average ratio (De)111/(De)100 approximately 2.0 signifies a fairly large contribution of stacking faults to the domain size broadening. For all the films more than 100 nm thick the 'apparent' orientation factor R approximately=3.0-4.0 indicates a preferential orientation of (111) planes parallel to the film surface.