High-performance self-aligned bottom-gate low-temperature poly-silicon thin-film transistors with excimer laser crystallization

Abstract

In this letter, high-performance bottom-gate (BG) low-temperature poly-silicon thin-film transistors (TFTs) with excimer laser crystallization have been demonstrated using self-aligned (SA) backside photolithography exposure. The grains with lateral grain size of about 0.75 mu m could be artificially grown in the channel region via the super-lateral-growth phenomenon fabricated by excimer laser irradiation. Consequently, SA-BG TFTs with the channel length of 1 pm exhibited field-effect mobility reaching 193 cm(2)/V center dot s without hydrogenation, while the mobility of the conventional non-SA-BG TFT and conventional SA top-gate one were about 17.8 and 103 cm(2)/V center dot s, respectively. Moreover, SA-BG TFTs showed higher device uniformity and wider process window owing to the homogenous lateral grains crystallized from the channel steps near the BG edges.