Title :
A novel four-mask-processed poly-Si TFT fabricated using excimer laser crystallization of an edge-thickened a-Si active island
Author :
Tien-Fu Chen ; Ching-Fa Yeh ; Chun-Yen Liu ; Jen-Chung Lou
Author_Institution :
Inst. of Electron., Nat. Chiao-Tung Univ., Taiwan
fDate :
6/1/2004 12:00:00 AM
Abstract :
A four-mask-processed polycrystalline silicon thin-film transistor (poly-Si TFT) is fabricated using 50-pulse KrF excimer laser to crystallize an edge-thickened amorphous silicon (a-Si) active island without any shrinkage. This method introduces a temperature gradient in the island to enlarge grains from the edge, especially when the channel width is narrow. The grain boundaries across the width of the channel suppress the leakage current and the drain-induced barrier lowering. Moreover, the proposed poly-Si TFT with a channel length of L = 2 μm and a channel width of W = 1.2 μm possesses a high field-effect mobility of 260 cm2/Vs and an on/off current ratio of 2.31 × 10/sup 8/.
Keywords :
amorphous semiconductors; excimer lasers; grain boundaries; leakage currents; silicon; thin film transistors; 1.2 micron; 2 micron; KrF excimer laser; a-Si spacer; anisotropic plasma etching; channel width; drain-induced barrier lowering; edge-thickened a-Si active island; excimer laser crystallization; four-mask-processed poly-Si TFT; grain boundaries; grain enlargement; high field-effect mobility; leakage current; on/off current ratio; polycrystalline silicon thin-film transistor; temperature gradient; Anisotropic magnetoresistance; Crystallization; Etching; Grain boundaries; Laser theory; Plasma applications; Plasma devices; Plasma temperature; Silicon; Thin film transistors;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2004.829026
