Analysis of thickness profiles of pulsed laser deposited metal films

Practically all theoretical approaches to pulsed laser deposition start on a condition which is extremely hard to realize in practice: that the target surface is smooth and plane. When using liquid (molten) targets, the problem of surface deterioration upon repetitive ablation can completely be solved, allowing for fair comparison of experiment and theory. In this paper measured thickness profiles of metal films deposited in vacuum from molten In, Sn, Bi and Sn-Bi alloy targets are compared with calculated distribution functions. The strictly symmetrical thickness profiles of tin and indium films, derived from two-dimensional optical density maps and Rutherford backscattering data are analysed in terms of Lorentzian-like functions, originating from the so-called shifted Maxwellian velocity distribution. The bismuth profiles show a characteristic deviation from this shape. (C) 1999 Elsevier Science B.V. All rights reserved.