Semiconductor device and manufacturing method thereof

摘要

The present invention provides a transistor having electrically stable characteristics. In addition, the reliability of a semiconductor device including such a transistor is increased. The semiconductor device includes a gate electrode layer, a gate insulating film over the gate electrode layer, an oxide semiconductor stacked film overlapping with the gate electrode layer with the gate insulating film provided therebetween, and a pair of electrode layers in contact with the oxide semiconductor stacked film. In the semiconductor device, the oxide semiconductor stacked film includes at least indium and includes a first oxide semiconductor layer, a second oxide semiconductor layer, and a third oxide semiconductor layer which are sequentially stacked. Further, the first oxide semiconductor layer has an amorphous structure, the second oxide semiconductor layer and the third oxide semiconductor layer include a crystal part whose c-axis is substantially perpendicular to a top surface of the oxide semiconductor stacked film.

主权项

1. A semiconductor device comprising:
a gate electrode layer; an oxide semiconductor stacked film overlapping with the gate electrode layer with a first insulating film therebetween; a source electrode layer and a drain electrode layer electrically connected to the oxide semiconductor stacked film; and a second insulating film overlapping with the oxide semiconductor stacked film, wherein the oxide semiconductor stacked film includes a first oxide semiconductor layer, a second oxide semiconductor layer, and a third oxide semiconductor layer which are sequentially stacked, wherein the third oxide semiconductor layer includes a first region in contact with a top surface of the second oxide semiconductor layer and a second region in contact with top surfaces of the source electrode layer and the drain electrode layer, wherein the second oxide semiconductor layer includes a first crystalline structure whose c-axis is aligned in a direction parallel to a normal vector of a surface of the second oxide semiconductor layer, and wherein the third oxide semiconductor layer includes a second crystalline structure whose c-axis is aligned in a direction parallel to a normal vector of a surface of the third oxide semiconductor layer.