Semiconductor device having oxide semiconductor layer and manufacturing method thereof

摘要

The invention provides an active matrix display device comprising a pixel portion including a thin film transistor having a multi-gate structure, the thin film transistor including a first gate electrode and a second gate electrode over a substrate wherein the first gate electrode and the second gate electrode are connected to each other; an insulating film over the first gate electrode and the second gate electrode; and an oxide semiconductor film over the first gate electrode and the second gate electrode with the insulating film interposed there between; a source electrode and a drain electrode formed on the oxide semiconductor film; and a pixel electrode electrically connected to one of the source electrode and the drain electrode; wherein each of the source electrode and the drain electrode comprises a titanium film formed on the oxide semiconductor film.