Thin Film

Thickness in this range places a film in a regime where surface and interface effects govern behaviour more than bulk properties do, and where optical interference between reflections from the two surfaces produces the visible colours of oxide layers and soap films. Deposition methods divide broadly into physical and chemical routes. Physical vapour deposition, including thermal evaporation and sputtering, transfers material from a source to the substrate without a chemical change; chemical vapour deposition builds the layer from reactive gas precursors on a heated substrate, and atomic layer deposition extends the idea to self-limiting single-monolayer cycles that give thickness control at the atomic scale. Applications span semiconductor device fabrication, anti-reflective and dielectric mirror coatings, photovoltaic absorber layers, and hard wear-resistant coatings on tools.