| 摘要 |
<p>The present invention provides a transistor, where an oxide semiconductor film is used, for preventing threshold voltage from being negative. A high quality semiconductor device having the transistor where the oxide semiconductor film is used is provided. An oxide semiconductor film having first to third domains is used to the transistor. The upper surface of the oxide semiconductor film of the first domain contacts a source electrode or a drain electrode. The upper surface of the oxide semiconductor film of the second domain contacts a protective insulating layer. Moreover, the thickness of the oxide semiconductor film of the second domain is uniform and smaller than the maximum film thickness of the first domain. Moreover, the upper surface and side surface of the oxide semiconductor film of the third domain contact the protective insulating film.</p> |
