Transistor with ZrO or HfO gate insulator sandwiched between two SiO or AIO gate insulators over an oxide semiconductor film

A semiconductor device comprising a transistor comprising:

• a first conductive film as a gate electrode of the transistor;
• a first insulating film over the first conductive film;
• a second insulating film over the first insulating film;
• a third insulating film over the second insulating film;
• an oxide semiconductor film over the third insulating film;
• a second conductive film electrically connected to the oxide semiconductor film;
• and
• a third conductive film electrically connected to the oxide semiconductor film,
• wherein the first insulating film and the third insulating film each comprise an oxide including silicon or an oxide including aluminum, and
• wherein the second insulating film comprises an oxide including gallium, an oxide including zirconium, or an oxide including hafnium.

A semiconductor device comprising a transistor comprising:

• an oxide semiconductor film;
• a first conductive film electrically connected to the oxide semiconductor film;
• a second conductive film electrically connected to the oxide semiconductor film;
• a first insulating film over the oxide semiconductor film, the first conductive film, and the second conductive film, the first insulating film comprising silicon oxide;
• a second insulating film over the first insulating film, the second insulating film comprising hafnium oxide;
• a third insulating film over the second insulating film, the third insulating film comprising aluminum oxide;
• and
• a third conductive film as a gate electrode of the transistor over the third insulating film.