High-Performance Self-Aligned Bottom-Gate Low-Temperature Poly-Silicon Thin-Film Transistors With Excimer Laser Crystallization

Chun-Chien Tsai, Hsu-Hsin Chen, Bo-Ting Chen, Huang-Chung Cheng
2007 IEEE Electron Device Letters  
In this letter, high-performance bottom-gate (BG) low-temperature poly-silicon thin-film transistors (TFTs) with excimer laser crystallization have been demonstrated using selfaligned (SA) backside photolithography exposure. The grains with lateral grain size of about 0.75 µm 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 µm exhibited field-effect mobility
more » ... -effect mobility reaching 193 cm 2 /V · 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 · 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. Index Terms-Bottom gate (BG), excimer laser crystallization (ELC), lateral grain growth, self-aligned (SA), thin-film transistor (TFT).
doi:10.1109/led.2007.899326 fatcat:2a2euyjyanf5viz44bm6rzq4ba