Thin-Film Transistor

What Does Thin-Film Transistor Mean?

A thin-film transistor (TFT) is a type of field-effect transistor that is usually used in a liquid crystal display (LCD). This type of display features a TFT for each individual pixel. These TFTs act as individual switches that allow the pixels to change state rapidly, making them turn on and off much more quickly. Because these TFTs are arranged in a matrix, they are called “active-matrix” TFT.


Techopedia Explains Thin-Film Transistor

Thin-film transistors are built by layering the thin films of an active semiconductor, hence the name, as well as a dielectric layer and some metallic contacts on a glass substrate. Glass is used because it is nonconductive with excellent optical clarity; it is also nonreactive to the chemicals used in semiconductor processing. In contrast, in the construction of a typical transistor, the substrate used is a semiconductor material, usually a silicon wafer.

Thin-film transistors are primarily used in LCD displays, which is why glass is used as the substrate. TFT technology is also used in both direct and indirect capture digital radiography detectors used in medical radiography. Active-matrix organic light-emitting diode (AMOLED) screens also have a TFT layer.


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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.