The effect of different scanning schemes on target and film properties in pulsed laser deposition of bismuth

Thin bismuth films have been prepared on glass substrates at room temperatu re by pulsed laser deposition with a Nd:YAG laser working at a wavelength o f 532 nm, The influence of both target diameter and the way of scanning the laser beam over the target surface on the film quality (droplet density an d film thickness homogeneity) was studied. Scanning electron microscopy and thickness profile analyses were performed on the films. Three different la ser beam scanning schemes have been simulated and tested. Films of high qua lity are obtained using the highest possible target area eroded in the most homogeneous way. This was achieved with an appropriate scanning of the las er beam over the target, for instance with a 'crenel' like scanning or with a scanning at varying speed. Results are discussed in relation to target r oughness. (C) 2000 Elsevier Science B.V. All rights reserved.