PURPOSE: To allow source and drain areas to be of an LLD structure and obtain a thin-film transistor with small off-leak current and large on-state current by setting the thickness of a gate insulation film and the concentration of impurities of lightly doped source area and lightly doped drain area to the range of specified values respectively.

CONSTITUTION: The thickness of gate insulation films 14, 24 and 34 is set to at least approx. 100 and at most approx. 1200. The impurity concentration of lightly doped source areas 111 and 211 and lightly doped drain areas 121 and 221 is set to at least approx. 0.5×1018cm-3 and at most approx. 2.4×1018cm-3. Further, since a P-type TFT 30 for driving circuit is preferably made to have a small off-leak current to suppress excessive power consumption, it is formed of an LDD structure.