Semiconductor device

摘要

Provided is a semiconductor device having a structure with which a decrease in electrical characteristics that becomes more significant with miniaturization can be suppressed. The semiconductor device includes a first oxide semiconductor film, a gate electrode overlapping with the first oxide semiconductor film, a first gate insulating film between the first oxide semiconductor film and the gate electrode, and a second gate insulating film between the first gate insulating film and the gate electrode. In the first gate insulating film, a peak appears at a diffraction angle 2θ of around 28° by X-ray diffraction. A band gap of the first oxide semiconductor film is smaller than a band gap of the first gate insulating film, and the band gap of the first gate insulating film is smaller than a band gap of the second gate insulating film.

主权项

1. A semiconductor device comprising:
a transistor comprising:
a first gate electrode;a semiconductor layer comprising a channel formation region and overlapping with the first gate electrode;a first insulating film between the first gate electrode and the semiconductor layer;a second insulating film between the first gate electrode and the first insulating film; anda source electrode and a drain electrode each in contact with a side surface of the semiconductor layer, wherein the semiconductor layer comprises indium, zinc, and oxygen, wherein the semiconductor layer comprises:
a first semiconductor film;a second semiconductor film over the first semiconductor film; anda third semiconductor film over the second semiconductor film, and wherein the first insulating film has a higher dielectric constant than the second insulating film.