Semiconductor device

A semiconductor device, comprising:

• a first gate electrode;
• a first insulating film over the first gate electrode;
• an oxide semiconductor film over the first insulating film;
• a second insulating film over the oxide semiconductor film;
• a metal oxide film over the second insulating film;
• a second gate electrode over the metal oxide film;
• and
• a third insulating film over the second gate electrode,
• wherein when an electron beam with a probe diameter of 1 nm is incident on the oxide semiconductor film, a plurality of spots are observed at a ring-like region in an electron diffraction pattern of the oxide semiconductor film,
• wherein the second gate electrode is in contact with the first gate electrode through an opening in the first insulating film, the second insulating film and the metal oxide film,
• wherein the third insulating film is a nitride film comprising at least one of hydrogen and fluorine,
• wherein the third insulating film is in contact with a top surface and a side surface of the second gate electrode, a side surface of the metal oxide film, a side surface of the second insulating film, and a part of a top surface of the oxide semiconductor film, and
• wherein the oxide semiconductor film comprises a channel region overlapping with the second gate electrode, a source region in contact with the third insulating film, and a drain region in contact with the third insulating film.