Semiconductor device

摘要

Provided is a highly reliable semiconductor device by giving stable electric characteristics to a transistor in which a semiconductor film whose threshold voltage is difficult to control is used as an active layer. By using a silicon oxide film having a negative fixed charge as a film in contact with the active layer of the transistor or a film in the vicinity of the active layer, a negative electric field is always applied to the active layer due to the negative fixed charge and the threshold voltage of the transistor can be shifted in the positive direction. Thus, the highly reliable semiconductor device can be manufactured by giving stable electric characteristics to the transistor.

主权项

1. A semiconductor device comprising:
a gate electrode; a gate insulating film over the gate electrode; a pair of electrodes over the gate insulating film; an oxide semiconductor film which at least partially overlaps with the gate electrode and is at least partially in contact with the pair of electrodes; and an insulating film over the oxide semiconductor film, wherein at least one of the gate insulating film and the insulating film includes a silicon oxide film having a negative fixed charge and an oxygen-excess silicon oxide film, wherein a first edge of the gate electrode, a second edge of the pair of electrodes, and a third edge of the oxide semiconductor film are parallel to a channel length direction when seen from above, and wherein the first edge is between the second edge and the third edge in a channel width direction when seen from above.