Patent ID: 8901554

Claim:
A semiconductor device comprising: an oxide semiconductor film that comprises a source region, a drain region and a channel formation region between the source region and the drain region, wherein each of the source region and the drain region comprises an impurity; an electrode electrically connected to the oxide semiconductor films, wherein the electrode is one of a source electrode and a drain electrode; a gate electrode over the oxide semiconductor film, the gate electrode overlapping with the channel formation region; a first insulating film over the oxide semiconductor film and the electrode, wherein the first insulating film is capable of supplying oxygen into the oxide semiconductor film, and is located between the oxide semiconductor film and the gate electrode; a second insulating film over the first insulating film; and a conductive film over the second insulating film, wherein the conductive film is electrically connected to the electrode through an opening of the first insulating film and an opening of the second insulating film, wherein a first angle between a side surface of the first insulating film and a bottom surface of the first insulating film at the opening of the first insulating film is larger than a second angle between a side surface of the second insulating film and a bottom surface of the second insulating film at the opening of the second insulating film, wherein the side surface of the first insulating film and the side surface of the second insulating film are in contact with the conductive film at the respective openings, and wherein the oxide semiconductor film comprises non-single crystals of an In—Ga—Zn-based oxide in which a c-axis is aligned in a direction substantially perpendicular to a surface of the oxide semiconductor film, wherein an a-axis of one of the non-single crystals is different from an a-axis of another of the non-single crystals, or a b-axis of one of the non-single crystals is different from a b-axis of another of the non-single crystals.