| abstract |
PROBLEM TO BE SOLVED: To provide a transistor having good electrical characteristics and a method for manufacturing the same in a transistor using an oxide semiconductor. SOLUTION: A first oxide insulating film is formed on a substrate, a first oxide semiconductor film is formed on the first oxide insulating film, and then heat treatment is performed to obtain the first oxide semiconductor film. A second oxide semiconductor in which a part of oxygen contained in the first oxide insulating film is diffused into the first oxide semiconductor film to reduce the hydrogen concentration and oxygen defects while desorbing the hydrogen contained in the first oxide semiconductor. Form a film. Next, the second oxide semiconductor film is selectively etched to form the third oxide semiconductor film, and then the second oxide insulating film is formed to select the second oxide insulating film. To form a protective film that covers the end of the third oxide semiconductor film. After that, a pair of electrodes, a gate insulating film, and a gate electrode are formed on the third oxide semiconductor film and the protective film. [Selection diagram] Fig. 1 |