| 摘要 |
PROBLEM TO BE SOLVED: To manufacture and provide a highly reliable semiconductor device which includes a thin film transistor having stable electric characteristics.SOLUTION: In a manufacturing method of a semiconductor device that includes a thin film transistor where a semiconductor layer including a channel formation region is an oxide semiconductor layer, heat treatment (heat treatment for dehydration or dehydrogenation) is performed which improves the purity of the oxide semiconductor layer, reduces impurities such as moisture, and also oxidizes the oxide semiconductor layer. The manufacturing method reduces not only impurities such as moisture in the oxide semiconductor layer but also those existing in a gate insulating layer, and further reduces impurities such as moisture existing in interfaces between the oxide semiconductor layer and films provided over and under and in contact with the oxide semiconductor layer. |
