High-Performance Excimer-Laser-Crystallized Polycrystalline Silicon Thin-Film Transistors with the Pre-Patterned Recessed Channel

Abstract

High-performance polycrystalline silicon (poly-Si) thin-film transistors (TFTs) have been achieved using an excimer laser crystallization method on a prepatterned recessed channel (RC). Such a prepatterned RC TFT exhibited an excellent field-effect mobility of 412 cm(2) V-1 s(-1) and an on/off current ratio higher than 1:1 x 10(8) as compared with 125 cm(2) V-1 s(-1) and 2:2 x 10(7) for the conventional ones, respectively. This is attributed to the two-dimensional control of the grain boundary location and the resultant cross-shaped grain boundary structures within the recessed regions. Therefore, the prepatterned RC TFTs with only one grain boundary parallel to the channel direction as the TFTs could be fabricated to avoid the perpendicular grain boundary. This technology is thus promising for the future applications of poly-Si TFTs in the system-on-panel (SOP) and three-dimensional integrated circuits (3D-ICs). (C) 2012 The Japan Society of Applied Physics