Novel Gate-All-Around Poly-Si TFTs With Multiple Nanowire Channels

Abstract

The novel gate-all-around (GAA) poly-Si thin-film transistors (TFTs) with multiple nanowire channels (MNCs) have been, for the first time, fabricated using a simple process to demonstrate high-performance electrical characteristics and high immunity to short-channel effects (SCEs). The nanowire channel with high body-thickness-to-width ratio (T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Fin</sub> /W <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Fin</sub> ), which is approximately equal to one, was realized only with a sidewall-spacer formation. Moreover, the unique suspending MNCs were also achieved to build the GAA structure. The resultant GAA-MNC TFTs showed outstanding three-dimensional (3-D) gate controllability and excellent electrical characteristics, which revealed a high on/off current ratio ( > 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8</sup> ), a low threshold voltage, a steep subthreshold swing, a near-free drain-induced barrier lowering, as well as an excellent SCE suppression. Therefore, such high-performance GAA-MNC TFTs are very suitable for applications in system-on-panel and 3-D circuits.