Semiconductor device and method for manufacturing the same

摘要

An object is to provide a semiconductor device in which characteristics of a driver circuit portion are improved while the aperture ratio of a pixel portion is increased. Alternatively, it is an object to provide a semiconductor device with low power consumption or to provide a semiconductor device in which the threshold voltage of a transistor can be controlled. The semiconductor device includes a substrate having an insulating surface, a pixel portion provided over the substrate, and at least some of driver circuits for driving the pixel portion. A transistor included in the pixel portion and a transistor included in the driver circuit are top-gate bottom-contact transistors. Electrodes and a semiconductor layer of the transistor in the pixel portion have light-transmitting properties. The resistance of electrodes in the driver circuit is lower than the electrodes included in the transistor in the pixel portion.