| abstract |
In the transistor including the oxide semiconductor film, a metal oxide film having an antistatic function and covering the source electrode and the drain electrode is formed in contact with the oxide semiconductor film, after which heat treatment is performed. Through the heat treatment, impurities such as hydrogen, moisture, hydroxyl groups, or hydrides are intentionally removed from the oxide semiconductor film, whereby the oxide semiconductor film becomes high purity. By providing the metal oxide film, generation of parasitic channels on the back channel side of the oxide semiconductor film in the transistor can be prevented. |