Methods for reducing droplet formation density on the surface of thin semiconductor films by pulse laser deposition: review

Abstract

The review discusses the most effective methods for reducing droplet density on the surface of thin films during pulsed laser deposition. This review highlights pulsed laser deposition as a promising technique for producing thin films from a wide range of materials. However, a significant challenge to its industrial application is the formation of droplets on the thin film surface. The primary causes of the droplet formation are identified, and a classification of methods to reduce the droplet density during pulsed laser deposition is provided. Completely eliminating droplets without compromising the quality or altering the stoichiometric composition of the thin films is exceedingly difficult, and no researchers have achieved this to date. The most effective strategy for reducing the droplet density involves optimizing the pulsed laser deposition parameters for specific material groups. Techniques such as using a segmented crystalline target, periodically rotating it at a specific speed, and employing excimer lasers at the energy densities slightly above the ablation threshold have been shown to reduce the droplet density on the thin film surface to as low as 10 3 cm-2 . The physical and chemical processes occurring on the target surface have the greatest impact on the droplet formation. Among active methods, high-speed filtration is the most effective, capable of reducing droplet density to approximately 2 10 3 cm-2 .