Editing MEMS (section)

=== Deposition processes ===

One of the basic building blocks in MEMS processing is the ability to deposit thin films of material with a thickness anywhere from one micrometre to about 100 micrometres. The NEMS process is the same, although the measurement of film deposition ranges from a few nanometres to one micrometre. There are two types of deposition processes, as follows.

==== Physical deposition ====

Physical vapor deposition ("PVD") consists of a process in which a material is removed from a target, and deposited on a surface. Techniques to do this include the process of [[sputtering]], in which an ion beam liberates atoms from a target, allowing them to move through the intervening space and deposit on the desired substrate, and [[Evaporation (deposition)|evaporation]], in which a material is evaporated from a target using either heat (thermal evaporation) or an electron beam (e-beam evaporation) in a vacuum system.

==== Chemical deposition ====

Chemical deposition techniques include [[chemical vapor deposition]] (CVD), in which a stream of source gas reacts on the substrate to grow the material desired. This can be further divided into categories depending on the details of the technique, for example LPCVD (low-pressure chemical vapor deposition) and PECVD ([[plasma-enhanced chemical vapor deposition]]). Oxide films can also be grown by the technique of [[thermal oxidation]], in which the (typically silicon) wafer is exposed to oxygen and/or steam, to grow a thin surface layer of [[silicon dioxide]].