Semiconductor device

摘要

An object is to provide a semiconductor device including an oxide semiconductor, which has stable electric characteristics and high reliability. In a transistor including an oxide semiconductor film, the oxide semiconductor film is subjected to dehydration or dehydrogenation performed by heat treatment. In addition, as a gate insulating film in contact with the oxide semiconductor film, an insulating film containing oxygen, preferably, a gate insulating film including a region containing oxygen with a higher proportion than the stoichiometric composition is used. Thus, oxygen is supplied from the gate insulating film to the oxide semiconductor film. Further, a metal oxide film is used as part of the gate insulating film, whereby reincorporation of an impurity such as hydrogen or water into the oxide semiconductor is suppressed.

主权项

1. A semiconductor device comprising:
a first gate electrode; a first metal oxide film over and in contact with the first gate electrode; a first insulating film containing oxygen over the first metal oxide film; an oxide semiconductor film over and in contact with the first insulating film containing oxygen; a second insulating film containing oxygen over the oxide semiconductor film; a second metal oxide film over the second insulating film containing oxygen, and a second gate electrode over the second metal oxide film, wherein the first metal oxide film contains at least one of aluminum and gallium, wherein the first metal oxide film comprises a region containing oxygen at a ratio exceeding a ratio of oxygen in a stoichiometric composition of the first metal oxide film, and wherein the second metal oxide film comprises a region containing oxygen at a ratio exceeding a ratio of oxygen in a stoichiometric composition of the second metal oxide film.