Flexible Thin-Film Transistors Produced from Silicon Wafers
Researchers with the Nanomanufacturing Systems for Mobile Computing and Mobile Energy Technologies (NASCENT) Engineering Research Center produced flexible, thin-film circuits from a standard, bulk silicon wafer chip.
NASCENT is a National Science Foundation-funded Nanosystems Engineering Research Center (NERC) and is headquartered at the University of Texas, Austin.
To continue advances in computing power, engineers are examining different ways to extend “Moore’s Law,” even as semiconductor components approach their theoretical smallest size. Flexible, thin microelectronics can fit increasingly compact circuitry in novel applications, such as portable, ultra-slim computing devices.
Researchers began by fabricating Complementary Metal Oxide Semiconductor (CMOS) devices on what is known as “bulk silicon” – a standard industry procedure for yielding multiple semiconductor chips from a single wafer of silicon.
Using an intricate process called exfoliation, researchers were able to skim off a specially prepared layer of the wafer that contained all the circuitry detail of the original, thicker piece. The new layer, made of silicon, was only between 20 and 30 micrometers thick and was flexible enough to be bent significantly without damaging the circuits embedded within the layer.
Thin-film transistors, or TFTs, already see wide use in display technology such as the LCD screens for computers and television sets. When embedded in flexible substrates such as polysilicon, the transistors could find use in a wide range of new applications, such as automatically updating newspapers and magazines capable of displaying rich media content.