DISPLAY DEVICE AND METHOD FOR MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To improve the aperture ratio of a display pixel by reducing the pattern size of a driving transistor of a light emitting element. SOLUTION: The second active layer 111 of a driving TFT 85 consists of two laminated polysilicon layers 102P, 103P. The upper polysilicon layer 103P is deposited simultaneously with a polysilicon layer constituting the first active layer 110 of a pixel selecting TFT 10 and has the same film thickness as that of the polysilicon layer concerned. Thereby the second active layer 111 is formed thicker for the portion of the film thickness of the lower polysilicon layer 102P. The average crystal grain size of the second active layer 111 is smaller than the average crystal grain size of the first active layer 110. Thereby the carrier mobility of the driving TFT 85 is smaller than the carrier mobility of the pixel selecting TFT 10. Consequently short channeling of the driving TFT 85 can be attained. COPYRIGHT: (C)2006,JPO&NCIPI