| 摘要 |
<p>One 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, a metal oxide film having a function of preventing electrification which is in contact with the oxide semiconductor film and covers a source electrode and a drain electrode is formed. Then, a halogen element is introduced (added) to at least one of the oxide semiconductor film, the metal oxide film and an interface therebetween via the metal oxide film and heat treatment is performed. Through these steps, impurities such as hydrogen, moisture, a hydroxyl group, or hydride are intentionally removed from the oxide semiconductor film, so that the oxide semiconductor film is highly purified. Further, by providing the metal oxide film, generation of a parasitic channel on a back channel side of the oxide semiconductor film can be prevented in the transistor.</p> |
