Patent Number: 6,166,399

Title: Active matrix device including thin film transistors

Abstract: A method of fabricating silicon TFTs (thin-film transistors) is disclosed. The method comprises a crystallization step by laser irradiation effected after the completion of the device structure. First, amorphous silicon TFTs are fabricated. In each of the TFTs, the channel formation region, the source and drain regions are exposed to laser radiation illuminated from above or below the substrate. Then, the laser radiation is illuminated to crystallize and activate the channel formation region, and source and drain regions. After the completion of the device structure, various electrical characteristics of the TFTs are controlled. Also, the amorphous TFTs can be changed into polysilicon TFTs.

Inventors: Zhang; Hongyong (Kanagawa, JP), Kusumoto; Naoto (Kanagawa, JP)

Assignee: Semiconductor Energy Laboratory Co., Ltd.

International Classification: H01L 21/20 (20060101); H01L 21/02 (20060101); H01L 21/336 (20060101); G02F 1/1362 (20060101); G02F 1/13 (20060101); H01L 29/66 (20060101); H01L 29/786 (20060101); H01L 029/04 (); H01L 031/036 (); H01L 031/0376 (); H01L 031/20 (); H01L 027/148 ()

Expiration Date: 12/26/2013