The thin film process can involve a number of different chemical or physical procedures. The most common thin film processing techniques are using liquid or gas chemicals, evaporation methods or the sputtering process. Combinations of these techniques are also common in the thin film process, which allows more control over the properties of the final product. The thin film process can be physical or chemical in nature.
Chemicals, either in liquid or gas forms, can be used to create a thin film. Chemical vapor deposition, for example, exposes a material to a chemical that decomposes or reacts to the material. There are often dangerous or volatile byproducts created during this process, so labs must be equipped to dispose of the resultant chemicals. Heating the substrate may enhance the growth of the thin film during chemical vapor deposition.
Evaporation is another common thin film process. In evaporation, the target material is heated until it evaporates or sublimates. Once the substance is a gas, it is released into a chamber that contains the substrate on which the thin film will form. The substance hits the substrate and forms a thin film.
There are a number of different machines that can be used to evaporate target materials. These machines can heat a target material on a heated coil, plate, or in a heated chamber. Substances can also be evaporated if they are hit by a beam of high intensity electrons or photons, such as those emitted by a laser.
The sputtering process, also called sputter deposition or reactive magnetron sputtering, is a commonly used thin film process. During this process, a substrate is placed in a vacuum chamber in a specialized machine. The air is vacuumed out of the chamber, and the target material is released into the chamber in the form of a gas. Strong magnets create a charge that causes the target material to ionize and deposit on the substrate. Moving the substrate back and forth during this process ensures that the thin film is evenly distributed on its surface.
The thin film process creates thin films of various elements or molecules that range between a few and a few hundred atoms thick. Thin films have many uses and are common components in computers, optical devices and as color filters for cameras and telescopes. Thin films are commonly made out of titanium, aluminum, gold, silver and alloys of these metals. Common substrates include metals, plastics, glass and ceramics.