| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device including an oxide semiconductor having stable electric characteristics.SOLUTION: With help of a halogen such as fluorine and chlorine, impurities such as hydrogen and moisture (hydrogen atoms, or a chemical compound containing hydrogen atoms such as HO) contained in an oxide semiconductor layer are removed from the oxide semiconductor layer, and the concentration of impurities in the oxide semiconductor layer is reduced. The oxide semiconductor layer can be formed by allowing the halogen to be included in a gate insulating layer and/or an insulating layer provided in contact with the oxide semiconductor layer, or the halogen may be attached to the oxide semiconductor layer by plasma treatment under a gas atmosphere containing halogens. |
