Epitaxy equipment is used in the process of epitaxial growth. This is a process of depositing a layer of crystal over a substrate through the method of chemical vapor deposition or some other similar technique. Epi is a form of epitaxy in which the deposited film is the same material as the substrate, and is used frequently in semiconductor fabrication. The process is done in order to improve bipolar device performance. When the epi layer is lightly doped over a more heavily doped silicon substrate, it results in a desired higher breakdown voltage across a collector-substrate junction, as well as a low collector resistance, which permits the system to act faster even with the same amount of energy.

The process of epitaxy works by manipulating chemical compounds and natural elements in order to develop this layer. The deposited film will take on a lattice structure that is identical to the substrate, separating the process from other thin-film deposition techniques. These films allow the substrate to operate with more speed and less energy. The film layers grown for semiconductors are often more pure than those grown through other forms of epitaxy, due to the way homoepitaxy works- by working with the same materials, when the crystalline structure is deposited, it does not have to alter its orientation as drastically.

Epitaxial growth requires an epi reactor in order to carry out chemical vapor deposition. Within the machine, there is a quartz reaction chamber, where a susceptor can be found, a device that absorbs electromagnetic energy and converts it to heat. The susceptor not only provides an overall uniform thermal distribution in order to keep the environment at a sustained temperature but also lends mechanical support to the wafer should it require it. The environment is then heated to a high temperature and the process gases are permitted to flow into the chamber. The film can then be deposited onto the substrate and epitaxial growth can take place.

Epitaxy can also occur with other techniques. The method mentioned above is called vapor-phase epitaxy, one of the most common forms. There are, however, other methods, including liquid-phase epitaxy, solid-phase epitaxy, and molecular-beam epitaxy. All of these are fairly self explanatory and can mostly occur within an epi reactor as well. It provides an environment that is ideal for epitaxial growth to take place and also can safely distribute gases to the chamber. Most importantly is the presence of a vacuum, specifically for molecular beam epitaxy.

Epi reactors and other epitaxy equipment are able to permit epitaxial growth and allow for a thin film to be deposited onto a substrate. These layers of film provide more efficiency and for processes to operate at a higher speed. With multiple different ways of creating epitaxial growth, the chosen method depends on the substrate. An epi reactor is generally the main piece of equipment used in epitaxial growth, but additional equipment may be required depending on the process (for example, cryopumps in molecular-beam epitaxy). Epitaxy equipment allows for growth to be manipulated and occur upon a substrate, giving it the thin film layers it needs.