| abstract |
A semiconductor device for high power applications is provided in which a novel semiconductor material having high mass production is provided. After the oxide semiconductor film is formed, a first heat treatment is performed on the exposed oxide semiconductor film to reduce impurities such as moisture or hydrogen in the oxide semiconductor film. Then, in order to further reduce impurities such as moisture or hydrogen in the oxide semiconductor film, oxygen is added to the oxide semiconductor film by an ion implantation method, an ion doping method, or the like, and then a second heat treatment is performed on the exposed oxide semiconductor film. It is carried out. |