A thin film device is any type of component based upon extremely thin layers of matter, usually that of semiconducting silicon, nanometers or billionths of a meter in thickness, and sometimes placed atop one another to form a complex thin film device or circuit. This can involve anything from transistor arrays used to make microprocessors for computers, to micro-electro-mechanical systems (MEMS), which are minute sensors used to detect everything from radon and smoke in home fire detectors to mechanical movement, temperature variations, altitude for guided missiles. Other applications for a thin film device include coatings, such as the silvering process for mirrors, optical layers to give lenses unique qualities, and magnetic films based upon iron compounds as a new form of computer memory. Advanced batteries, pharmaceutical drugs, and solar cell applications, such as rooftop tiles that generate their own electrical power, are also based on a thin film device of one form or another.
Various chemical, physical, and electrically-based methods exist for generating thin films, some of which are capable of depositing film layers down to the finite level of single atoms. The earliest forms of commercial success for thin film deposition involved silicon semiconductor compounds. Pure silicon, as a complete insulator, is doped or implanted with individual ions of phosphorus or boron at a rate of one atom of phosphorus or boron to every one-billion atoms of silicon, to give the thin film semiconducting electrical properties. New methods of thin film deposition now involve creating extremely fine layers of polymer compounds, which have applications for flexible solar cells and organic light emitting diodes (OLED) that are used to create display panels for televisions, computer monitors, and electrical billboards.
The process of thin film deposition is a very exacting and precise science, due in some part to the delicate material most commonly used to produce thin film device components, semiconducting grade silicon (SGS). Decades of research and development in this arena has made it possible to adapt thin film technology to new arenas of materials science. Using thin film deposition manufacturing knowledge coupled with advances in nanotechnology research has led to a increasingly wide range of thin film device applications.
Microdots are being generated and placed on drug containers to prevent the importation of counterfeit pharmaceuticals, and thin films are now incorporated into anti-counterfeiting efforts with money. Medical implants, such as stents, are a thin film device for enhancing blood flow in arteries, coated with microscopic layers of powerful medications for slow release into the blood stream. From uses in toxicology testing to delivery of powerful anti-cancer drugs in extremely small amounts that would otherwise be deadly, to the weaving of gold and silver thin films into luxury fabrics, the thin film device concept is being applied across a proliferating range of fields and industries that often go unnoticed by the public due to their extremely small size and hidden functions.