Poly and Nano-crystalline High Electron Mobility Thin Film Transistors on Plastic Substrates for Large Area Applications

Abstract

AbstractThin-film transistors (TFT) of poly and nano crystalline silicon have been made at temperature as low as 170°C on flexible PET (polyethylene terephthalate) substrates.The crystallization of the silicon film has been achieved using external mechanical stress assisted by a plasma hydrogenation technique. The formation of TFT is possible by means of a lateral crystallization of amorphous silicon under the channel region. High mobility TFTs with an electron mobility of 25cm2/Vs and an on/off ratio of 2000 have been obtained. Scanning electron microscopy, X-ray diffraction analysis and optical microscopy have been used to examine the crystallinity of the layer. In addition we report the deposition of high quality low-temperature silicon-oxide layers on PET substrates using an RF-plasma enhanced chemical vapor deposition unit with direct introduction of oxygen gas into the chamber and its reaction with Silane. Infrared spectroscopy was used to examine the quality of the oxide layer.