Semiconductor device

摘要

An object is to provide a semiconductor device using an oxide semiconductor having stable electric characteristics and high reliability. A transistor including the oxide semiconductor film in which a top surface portion of the oxide semiconductor film is provided with a metal oxide film containing a constituent similar to that of the oxide semiconductor film and functioning as a channel protective film is provided. In addition, the oxide semiconductor film used for an active layer of the transistor is an oxide semiconductor film highly purified to be electrically i-type (intrinsic) by heat treatment in which impurities such as hydrogen, moisture, a hydroxyl group, or a hydride are removed from the oxide semiconductor and oxygen which is a major constituent of the oxide semiconductor and is reduced concurrently with a step of removing impurities is supplied.

主权项

1. A display device comprising:
a pixel electrode; and a transistor, wherein the transistor comprises:
a gate electrode;a gate insulating film over the gate electrode;an oxide semiconductor film including a channel formation region;a metal oxide film over the oxide semiconductor film; anda source electrode and a drain electrode over and in contact with the oxide semiconductor film and the metal oxide film,wherein the metal oxide film overlaps the channel formation region,wherein the oxide semiconductor film contains one or more metal elements, andwherein the metal oxide film contains at least one of the metal elements contained in the oxide semiconductor film, and wherein the pixel electrode is electrically connected to one of the source electrode and the drain electrode.