Comparison of large-area pulsed-laser deposition approaches

The popularity of Pulsed Laser Deposition (PLD) as a thin film growth technique has dramatically increased over the last six years and proponents of more mature physical vapor deposition processes are quick to point out the main 'draw-back' of PLD--the apparent difficulty in scaling up the process to areas compatible with commercial applications. To date the main focus of PLD has been on its application to the growth and characterization of epitaxial thin films of a variety of chemical compounds, as well as obtaining an understanding of plume dynamics, while relatively little attention has been paid to the issue of scale-up. However, three basic approaches dealing with scaling-up the thin film growth process of pulsed-laser deposition have been reported in the literature. These include rastering the laser beam over a large area target, translation of the substrate with respect to the ablation plume, and 'off-axis' deposition. Each of these approaches has produced quality thin films of the high temperature superconducting oxides as well as other materials over substrate sizes of at least two-inches in diameter. This paper will compare these three basic approaches, and discuss the advantages and draw backs of each. Issues such as film thickness and composition profiles, reproducibility, deposition rate, substrate heating, and target resurfacing will be addressed. Projections to further scale-up of this physical vapor deposition technique will be presented.