A new poly-Si TFT with selectively doped channel fabricated by novel excimer laser annealing

A new excimer laser annealing method, which results in a single grain boundary in the channel of polycrystalline silicon thin film transistor (poly-Si TFT), is proposed. The proposed method employs lateral grain growth through aluminum patterns on an amorphous silicon layer. The aluminum pattern acts as a selective beam mask and a lateral heat sink during the laser irradiation. Poly-Si TFTs fabricated by the proposed ELA method exhibit considerably improved characteristics, such as the high field effect mobility exceeding 240 cm/sup 2//V sec. The turn-off characteristics have also been improved by the field-reducing structure.