An X-ray profile analysis on the growth imperfections and internal strainsin vapour-deposited lead films

Detailed X-Ray line profile studies have been performed on thin films of le ad (thickness range similar to 30-900 nm), vapour-deposited onto glass subs trates, under high vacuum (similar to 10(-6) Torr). The films reveal unusua lly high orientation along [111] over the whole thickness range. Both Warre n-Averbach and Williamson-Hall analysis have been adopted. W-H plot shows a near-isotropy in strain broadening observed at higher film thickness with predominant microstrain contribution. W-A analysis shows that the crystalli te sizes are in the range of 225-2700 Angstrom and the rms strains are of t he order of 10(-4). The residual stresses have been found to be small and s lightly higher than that due to thermal stress. The combined peak shift, pe ak asymmetry and peak broadening analyses show the absence of both intrinsi c and extrinsic stacking faults while growth faults are found to be present in smaller concentrations. The lattice parameter changes are small and are of the order of 10(-4). The dislocation density calculated from crystallit e sizes and rms strains is of the order of 10(10)cm/cm(3). Dislocations are the primary cause of strain broadening. The dislocation arrangement change d considerably from a non-random to a near-random distribution with increas ing thickness. The microstrain distribution function was however found to b e almost Gaussian.