A thin film is a metal or metal-ceramic layer of material that is deposited, atom-by-atom, on the surface of a substrate. The thin film forms a bonded layer that changes the part’s appearance, durablity or function.
Thin films don’t affect dimensional tolerance or the substrate’s desired textures. They are used to improve a product’s color, light reflection or refraction, hardness or electrical insulation and conductance.
Thin film thickness ranges from fractions of a nanometer (1 nm = 0.000000001 m = 10 angstroms) to several micrometers (1 μm = 0.000001 m). For reference, the diameter of a human hair ranges from 17-181 μm. A strand of spider web silk has a width of 3 to 8 μm.
The controlled synthesis of materials as thin films (a process referred to as “deposition”) is a crucial need in many industries. For example, architectural glass, displays, touch panels and solar cells all contain thin films. A familiar example is a mirror, which typically has a thin metal coating on the back of a sheet of glass to form a reflective interface.
The most important coating process to produce thin film coating is a type of PHYSICAL VAPOR DEPOSITION called SPUTTER DEPOSITION, or sputtering.
