thinfilm

A thinfilm is a layer of material with thickness much less than its lateral dimensions, typically from a few nanometers to a few micrometers, deposited on a substrate. Thinfilms are defined by their interfaces and by properties that differ from the bulk due to confinement and interfacial effects.

Common fabrication methods include physical vapor deposition (PVD; evaporation and sputtering), chemical vapor deposition (CVD), and atomic layer deposition (ALD); as well as solution-based approaches such as spin coating and dip coating. The method affects conformality, roughness, film stress, and thickness control.

Optical thinfilms cause interference and are used for coatings with specific reflectance or transmission. Dielectric and metallic thinfilms determine electrical behavior and shielding. Mechanical properties such as hardness and adhesion influence durability.

Applications include optical coatings, photovoltaics and LEDs, protective and wear-resistant coatings, microelectromechanical systems, sensors, and barrier films. Materials commonly used are SiO2, TiO2, Al2O3, Si, Ge, Au, Ag, and organic semiconductors.

Characterization methods include ellipsometry, profilometry, AFM, and electron microscopy; cross-sectional TEM can reveal thickness and interfaces. Common challenges are achieving uniform thickness on complex geometries, controlling stress, preventing diffusion at interfaces, and ensuring long-term stability.